Really want answer on finished side, was going to leave unfinshed side bear. Definitely no fiberglass with the exception of an interior separation wall. Most likely, the best approach is framing in front of the steel. I was afraid you were going to say in front of steel beams better, seems alot easier then to hang drywall, but losing roughly 60sq ft of a small basement area.
Is was just tuckpointed last year, should I paint it with waterproofing paint 1st? Did you ever solve this or come up with a solution? Then, insulating using closed-cell spray foam in the gaps, encasing the studs and beams. I imagine this would result in — at best — cold spots on the wall, and at worst condensation problems from the warm interior air hitting the colder steel.
What did you end up doing? Any thoughts on my approach described above? I have filled all rod holes and fixed all cracks. No noticeable moisture coming through wall. Spraying is close to double the cost of this product. This product will also be cold, any moisture that gets into the stud cavity will condense against it.
The old saying still stands true….. Great Site, Thanks! I am replacing a shower in a sub-grade basement. I have taken out the old stand alone shower stall and have cleaned down to bare studs. One wall is a poured concrete wall. There were 1 x 3 strips nailed to the concrete and then sheet rock. What should be on my inside studded walls water-board?
How should I treat the concrete wall? I am concerned about moisture from the concrete wall and moisture from the shower side enclosure? Thanks in advance. Keep up the good work. JG — Are you putting in a stand alone shower or tiling?
Whether you frame a wall, or use strapping furring , the key is the foam, properly sealed. The interior wall, that really depends on the type of shower.
Todd — I have find the website to be extremely informative. I want to ask your opinion on our basement in Michigan. We do use a dehumidifier. I have read by your accounts and others not to use Fiber. Is that necessary? I was not going to add a vapor barrier or anything else. I would then drywall over the wall studs build into the wall.
Do you think this is sufficient enough or do I need to go thicker? I have read some others add foam and them un-faced fiber over the foam to bring a higher r value. Lastly, is this the best way to go about it. Thank you! Having said that, it seems that foam would be the best approach.
Nice forum. I want to get your suggestion on my specifics before I finish my walkout basement in KY. There are poured foundation walls below grade and studded walls with unfaced batt insulation above grade. First, what do i do with the concrete walls… poly vapor barrier then frame and unfaced batt -or- xps foamboard then frame and maybe more unfaced batt? Second, for the above grade… do i leave as is or do i need to put poly over it?
Third, what is best way to sound-proof between basement and level above? Finally, do you have any suggestions on radon systems? Poly has no place in a basement, ever! We almost always pipe radon vents out though the roof. I have a new house in WI. Can I cut 1. Be sure all the seams are taped and sealed. Space is optional. NO poly over the fiberglass. So I have a 20o year old cabin in the Adirondacks.
The stone foundation leaks horribly and has for many years before me. It comes in and goes out via sump pump. Problem is horrible smells of mold and poor air even sitting on first floor. Can I put closed cell boards in floor joist bays and seal w spray at edges to create a barrier from basement air to the rest of house?
Maybe spray w paint sprayer all first then enclose w boards then paint all basement again to seal since scrubbing has only done so much. Jason — Honestly, the first thing I recommend is finding a way to control water. Due to grades the only practical way requires an excavator and probably few hundred feet of perforated pipe, clean stone for the trench etc. For my timeline prior to my wife giving birth I must clean the air on the first floor. In time I do plan on dealing w moisture properly for future air issues.
But the damage is already done down there and I need to seal us apart before I can clean that air properly. So would that create a Barrier fro. The bad air, at least some, and not be a complete waste of money. But vapir barrier well, I am free. I guess one approach would be to try and paint all of it with BIN primer. Then install the foam from below and seal it.
It seems some better ventilation down there might help as well. My basement is already framed, should I try to use the 2 inch pink insulation if I can get it in? I have one room dedicated for a wine cellar, my plan was to skip any type of insulation and just drywall it. Is that a good idea? I would NOT skip the insulation in the wine cellar.
Hi Todd, I now have stud up, about an inch and two quarters off the wall. Electrical rough and plumbing have been done. I have a walk out basement also. If I do decide to go with this, do I use rigid foam on all concrete walls below grade and exterior walkout?
Plus I notice behind the tub, it looks like my contractor just stuffed fiberglass back there. Should there be something bwtn studs and tub in shower? I am wondering the correct method of insulating a building a basement wall. If you could outline what exact material I should be using, that would be great! Currently, there is insulation with Poly 6 coming halfway down the wall from the top, leaving the bottom half as bare concrete.
Should this be removed first? There are just small windows in the basement. Joe — I would definitely remove the batt insulation. I purchased an older home and the previous owner farmed and insulated the walls with fiber glass of course. The problem is he put vapour barrier on both sides of the insulation. My question is: will it be fine if I leave it that way or should I gut the whole basement and do it right.
Because of the time, expense, the furniture and alliances that need to be moved I am leaning towards leaving it. What r my options and will it make the basement warmer if I change it. Foam would be the approach to use, and the warmth depends on the final effective R value. I have a tri level home I built it in recently I decided to replace wall covering in the family room I have furring strips every 16 inches the upper part 2x6s I have 6 inch bats there fiberglass the pink side is facing out vapor barrier in the bottom half I used 1 inch strofoam over the fiberglass and behind the foam I had some termite damage this has all been repaired my question is the fiberglass looks fine to me but does age come into play I have removed foam an replacing it should I replace fiber glass also?
Are you saying you have a wall that the lower half is concrete with furing strips? Good luck.. Good summary! I then used closed cell spray foam dual propane sized cans and sprayed the stud cavities and got behind the studs as well forming a impervious seat from the basement wall to each stud cavity.
I then used R19 fiberglass insulation and filled the stud cavities and any other crevasses. Still smells like a basement probably because the boiler room is not finished on the exterior walls.
I know it is well insulated because the lights increase the room temp degrees. Todd, I just bought a new construction home and want to finish the basement soon. I live in a a desert state Utah , but am always concerned about mold though the lack of humidity in the air usually, but not always, reduces the chance of mold.
The builder put batt fiberglass insulation and used thick plastic to keep it held against all the below grade walls diaper style. Obviously, removing all of that will take quite the dumpster and a large amount of money to replace with XPS. First question: is it worth the switch to XPS? Second question: do I put a pressure treated board against the concrete and have the XPS sit on top of that, or does the XPS go all the way from the ceiling joist to the bare concrete floor?
Third question: on the building science article, it mentions that XPS is highly flammable, and that gypsum board should be placed for fire protection. My question is, do I need the gypsum, or will Sheetrock do the same job? Last question: I have several sewer drains that are right up against the concrete no way to put the XPS behind them what do I do in that situation? Thanks for all the help in advance!!!
Foam insulation should be protected from fire. Drywall and gypsum board are the same thing. Building codes vary from region to region so you need to check yours on how much of a thermal barrier is required. Great site and great discussion. Thanks for taking the time to help people. Some context… Our house is in southern Ontario, and at present it has pink bats inside the basement walls with a black matting separating them from the concrete block foundation.
Also get readings from places where chimneys, porches, garages, and patios attach to the house. Whether coverage is available or not, fitting black mold removal costs into the budget is key to protecting the most valuable of investments.
Here is my homepage — mold removal San Diego. After that, I was going to install my stud wall right against the Owens Corning board with no batt insulation. Is the r-matte on my walls the same thing? Would you recommend taking it all down? What do you think about installing the owens corning board up against the Polyiso boards? Do I need to add batt insulation in addition to the 1. We recently had a flood across our entire basement floor approx 2 inches high.
Contractors we have met with have recommended and since started removing the the bottom 2 ft of drywall and batt insulation and the plan is to replace the same new materials except with mould resistant gysupm.
Is the spray foam still possible? Any thoughts would be greatly appreciated. Thank you Sir, for really educating me on insulation matters. I had the misfortune of discovering a leak in my basement and it turned out that the main water shut off valve sprung a leak and soaked the drywall and insulation underneath. Further investigation revealed that there is plenty of poly moisture barrier.
And yes, the basement is below grade. Not only is there poly against the block wall, there was also plastic sheeting between insulation and drywall. I want to follow your advice and use rigid insulation. What do you suggest for insulating around the copper water pipe? I noticed you would never recommend poly in a basement, but I was what you would do in my situation. My basement is below grade and contains a 45 foot long french drain against the wall with no poly to force the water to run into the drain.
Could I use rigid foam insulation from the sill plate to the trench and expect the water would still make it to the drain and not adversely affect the xps if it is sitting in standing water or should I place poly from the inside side of the trench up the wall a couple of feet to isolate the drain and then place rigid foam on top of the poly? When my home was built, the basement concrete exterior walls had 1 inch rigid foamular board attached.
All electrical, low voltage, and central vac items have already been ran in the walls. Will the 1 inch be enough vapor barrier to just add more batts of insulation, or should I spray foam on top of the rigid foam board? I am located in Northern Indiana. I bought a sq. The house is 1 story, cinder block, tar-pebble roof. Half of the house is half into the ground. I guess due to the 16 degree incline on the land.
The entire house is covered with cheap wood paneling. The most in the ground corner upper right if you were looking at a rectangle is also where the bedroom is. I have read a lot and cannot come to a decision as to what to do exactly to insulate and cover the walls if possible with something other than drywall because it is heavy.
I have a great chance to start new and do it correctly. Have well insulated and dry walls. The project at this point is a blank canvas. I thought about painting with sealer first. The installing Canadian style panels to insulate and then covering with drywall IF I cannot find something that will be better and easier to work with and that will contribute to the R value for insulation.
Thank you for your forum and for sharing your knowledge. It is relief to be able to read it and learn. I insulated a basement exactly as you described before reading this by the way and had a building inspector tell me that i was not allowed to use vapor barrier below grade. Fantastic article. We have had the location sprayed and nest destroyed but I remain somewhat worried about using the foam option given the expence and the chance for a repeat infestation the whole neighbourhood shares this issue.
I live in southern Ontario so humidity and varying temperature is the norm. Todd — I built a cement patio outside of two cellar windows. They were never sealed. I notice mold between the glass and outside. What is the best way to seal the windows? House is yrs old wooden type. No basement, however lower level is split. Location is upstate NY North of Albany. Moved here 4 yrs ago and have found the winters rather cold.
Looking to insulate at least the lower level. The bottom plate should sit on top of the extension of the house wrap and on a continuous impermeable membrane such as a sill gasket see Figure Next, fasten the top plate to the bottom of the joists. Where the wall runs parallel to the joists you will have to build in a nailing support for the top plate the approach you use will depend upon your particular house.
Now is the time to square up the walls. If your home is in an area of expansive clay soils, you may have to include a 25 mm 1 in. Talk with your local building authorities about how to best handle this situation. Next, install the studs mm 24 in. Confirm that this spacing will offer structural support for your finishing needs. Make sure that the studs are perfectly vertical and accurately spaced so that the insulation will fit snugly and the finish can be installed without problems.
Measure each stud separately. Extra framing is needed around doors in the foundation, but window openings only need a single stud, as the wall is non-load bearing.
If all alignments are perfectly level and square and there are no obstructions, you may be able to build the wall on the floor, tilt it into place, shim the bottom plate and secure the wall frame in place. Then install any required wiring and plumbing rough-ins.
If you left a space behind the frame for batt insulation, you can now add the insulation between the studs and the wall in a horizontal layer. The insulation must be tight against the foundation wall. Next, fill the frame wall with a vertical layer of batt insulation fitting it snugly between the studs, allowing no gaps, air spaces or over-compression.
Install a vapour barrier over the studs and insulation. In basements that have proven to be dry, a polyethylene vapour barrier is suitable. However, if you have any doubts or there is a risk of dampness in the basement, there are two alternate methods that may be better suited. The first alternate method is to use polyamide sheeting, a breathable membrane also known as Nylon-6 vapour retarder film or smart barrier. When installed on the warm side of an exterior wall, smart barrier has a water vapour permeance that changes with the conditions within the wall.
If the relative humidity in the wall cavity increases, the smart barrier will allow the wall to dry out toward the interior unlike other sheet-type vapour barriers. Leave enough of either the polyethylene or smart barrier at the top to connect to the air barrier in the joist header space. Seal all edges, seams and penetrations with acoustical sealant or other approved materials. All joints should overlap over a stud and be sealed with a continuous bead of sealant that is run between the layers of material at the lapped joints.
Staple the barrier to the stud through the bead of sealant see detail in Figure The second alternate method is to use an air and vapour barrier system known as the airtight drywall approach ADA. The ADA method uses rigid materials, typically drywall, very carefully and thoroughly sealed to the framing and all other component connections by using adhesive-backed foam tape and flexible caulking. Attention to detail is critical. The ADA method works only if it is completely sealed and tied into the air and vapour barrier system in the rest of the house.
The following is a non-inclusive list of ADA sealing considerations:. This method involves gluing rigid board insulation to the foundation wall and then covering it with a frame wall incorporating batt insulation. The result is higher insulation values with less loss of interior space, a very good reduction of thermal bridging and no need for an additional moisture barrier.
It works best if the basement wall is even and vertical i. Use only moisture-resistant board insulation such as extruded polystyrene or Type IV expanded polystyrene. Follow the preparations required in Part 6. Using rigid board insulation with at least RSI 1. If any mould were to develop behind the insulation it would be contained. Special mechanical fasteners can be used if you have any sensitivity to the glue. Install the insulation snugly to eliminate air circulation at the edges.
Use urethane foam sealant and technical tape to seal all joints and interParts of the foam board. Next, install the wood-frame wall directly in contact with the rigid board insulation. Follow the techniques detailed in Part 6. The frame wall can now be roughed in for any wiring and plumbing and insulated as noted previously in Part 6.
For details on treating the joist area, see Part 6. Do not use a polyethylene air and vapour barrier with this approach, as there is a risk of creating a double vapour barrier with the foam board.
Instead, use either the smart barrier or the ADA method. If you are using smart barrier, leave enough of the film at the top to connect to the air barrier in the joist space. If you are using the ADA method, pay strict attention to proper air and vapour sealing, including a layer of vapour barrier paint. Any exposed foam insulation may require fire protection as per code requirements. This is becoming a popular hybrid method of insulating.
It involves building a frame wall 25 to 50 mm 1 to 2 in. The spray foam fills and bonds directly to the framing members and the wall, offering high insulation value about RSI 0. The frame wall is then filled with insulation.
The primary limitation of this approach is higher cost, although its use reduces the need for additional materials and labour see Figure Discuss with the spray foam contactor on site what should be done before starting the spraying.
Major issues such as active structural cracks and frequent and major water leaks must be addressed first. Install the wood frame wall at a distance from the foundation as directed by the contractor, including both sides of the corner studs.
Follow the framing techniques discussed in Part 6. Once the contractor has installed the foam, the frame wall can be roughed in for wiring and plumbing and insulated.
Again, a polyethylene vapour barrier is not recommended. For finishing, see the previous frame wall method in Part 6. The joist header space is also called the rim joist space, foundation header space or simply the joist space. This is the area where the floor joists intersect and are supported by the foundation walls in both basements and crawl spaces. Put simply, it is the area where the house structure rests on the foundation.
This area is prone to air leakage and is seldom properly insulated, resulting in unwanted drafts, dust and pollen entry and vermin access. There are three major joint configurations, each with implications on how best to air seal and insulate:. If it is not possible to extend the exterior foundation insulation to cover the full header joist area, the space will have to be insulated and sealed from the inside.
If the foundation walls are insulated from the interior, the air and vapour barrier must be continuous for the wall and header space. For fully-embedded joists, do not exceed a maximum of 25 mm 1 in. For all the approaches illustrated in Figure and Figure , building codes may mandate levels of insulation, so check with your local authorities as to the recommended levels and practices. Polyurethane spray foam installed by a certified contractor offers excellent air sealing and insulation of this space.
However, the foam must be covered with fire-resistant material if it is not covered by the basement ceiling. An irregular basement is usually made of stone or rubble and is rarely waterproofed on the outside see Figure While an exterior retrofit is always recommended, it may be possible to insulate on the inside if there are no water or moisture problems. Figure Insulating a pony wall is a two-step process that creates a small ledge.
First, cover the interior wall with cement-based parging to smooth the surface and to protect the existing mortar. Then build a frame wall, add a maximum of RSI 2. In general, do not go with higher insulation values as there is a risk that the wall may be subjected to damaging freeze-thaw cycles. Check with your local building authorities for more information on how to deal with this potential problem. Closed-cell spray polyurethane foam has been used successfully to reduce dampness problems for rubble walls while offering some thermal protection value.
Do not exceed RSI 2. This product must be installed by a certified installer and be covered by an appropriate fire-resistant material. For very wet basements prone to flooding and high moisture problems, it may be best not to insulate the basement walls. Instead, consult your building authorities and an experienced general contractor about the potential to treat the floor joist space as an exposed and insulated floor.
Apply the insulation to the cold cellar or garage wall separating the heated basement from the unheated space, as if it were an external wall. Insulate the ceiling as described in Part 6. If you insulate your cold cellar, check on the winter temperature so you can make adjustments to prevent freezing.
If the room is still too warm or the floor above is cold, you may want to insulate the ceiling of the cold room see Part 6. A pony wall consists of a short wood frame wall sitting on top of a conventional concrete foundation. In this case, the wood frame Part is insulated between the studs, and the concrete Part is insulated on the interior assuming there are no moisture problems.
The insulation on the concrete is extended up about mm 8 in. A ledge is created at this point see Figure To avoid a ledge, install a frame wall from floor to ceiling and fill the cavity with insulation. Seal and insulate floors that overhang the foundation. It is usually possible to remove the finish underneath the overhang and air seal the space between the joists above the foundation with polyurethane foam or with caulked, low-permeability rigid insulation.
Insulate the joist space with batt or blanket insulation and add an air barrier before re-installing the finish. In some cases, a layer of rigid board insulation with protective outer finish can be applied to the underside of the overhang, but the space should still be air sealed and insulated. Alternatively, a contractor can spray foam into the cavities or blow in dense-pack fibre insulation though holes drilled to the underside. As most heat is lost through the upper part of the foundation walls, basement floor slabs are seldom insulated.
For improved comfort, moisture control and radon reduction, apply a moisture barrier to the floor or seal the floor to prevent moisture accumulation between the insulation and the slab. Alternatively, you may install a floor drainage system under the new floor. If you are installing or replacing a concrete slab floor, this offers an excellent opportunity to have in-floor heating installed or to have it made radiant-ready.
Radiant-ready is where insulation and heating lines are installed before pouring the new slab, allowing for future use of radiant heat including solar-generated in this area. Consult a heating contractor with experience in hydronic in-floor heating. Medium- and high-density polyurethane foams are sometimes used in basements and crawl spaces that have poured concrete, concrete block, brick or rubble walls and are not intended to be living space. In these cases, spray foam is installed directly on the foundation wall and then sprayed with a non-flammable covering to meet local code requirements.
As a general rule, treat heated crawl spaces as short — sometimes very short — basements and renovate them as described earlier in this chapter. Fix any water leaks and remove sources of water infiltration as noted in Part 2. Insulating the walls is recommended to avoid having to insulate and protect all plumbing pipes and heating distribution systems. Walls can be insulated externally to reduce the internal moisture problems that can develop in damp crawl spaces and to keep the soil below the footings warm.
It is also usually easier to insulate the walls than the ceiling above, especially in tight crawl spaces or where joist spacing is uneven. Walls tend to require fewer materials than ceilings.
If there is no moisture barrier on the crawl space floor, add one. The minimum barrier should be 0. I am going to finish the basement myself. My concern is insulating the floor. I don't want to use treated wood as batten due to I know how it curls when drying. It would take a lot of screws to keep flat.
Is there anthing wrong with what I propose? Lay a plastic vapor barrier down. Put 2" foam boards down. Screw both sheets together and have carpet installed on top? Is it ok? Is it overkill? Does the plywood need to be moisure resistant? If you have a layer of poly and then 2 inches of EPS foam, I wouldn't be too concerned about the plywood as I think you have separated it well from any chance of moisture assuming the following : If it's a new basement you are building, then presumably you have the opportunity to take some additional steps towards protecting it, meaning - proper exterior water protection, drainage, a weeping tile that can drain bulk water away from the foundation, and a sump pump.
But I do wonder if you won't find it a bit spongy if you have a plywood subfloor laying directly on a couple of inches of foam. If you take the steps to protect it from flooding in the first place, I might also consider the idea of laying down a water proof dimple membrane with a bit of space for any incidental water to move, then some 2x3s with insulation boards between them, then your plywood subfloor. I recently framed my basement walls with 2" of eps foam fastened to the exterior wall with all seams taped and corners spray foamed.
I left a 1" gap between the foam and framing and when I insulated the walls with r12 batt insulation I noticed moisture forming behind the insualtion where the insulation was contacting the foam. What would be causing this? And what should the next course of action be to correct this?? Correct that if any of it is wrong, and, do you have a 6-mil poly barrier sealing the whole wall together?
You have a source of moisture somewhere and it's a case of finding it, but also a matter of letting it out. Poly vapor barriers on the interior surface of a basement wall are not at all a good idea, it will trap the moisture. So if you have one, that's at least part of what is causing the problem. Better is if moisture in a wall can dry to the interior since it can't dry to the exterior , and then it can be handled by ventilation equipment or dehumidifiers.
Without a poly barrier the moisture shoud be able to dry to the interior, unless there is something else really wrong going on here. I noticed moisture was forming where batts were contacting the foam. I'm thinking this is due to the warm batt touching the cool styrofoam and creating condensation. I've also just had an HRV installed but don't want to hook it up until the basement is taped.
Will and HRV correct this or am I overthinking it? I would just hate to finish the basement and have issues when this would be the time to solve them and correct it.
Is the concrete floor in the wall and 1 inch gap area insulated or exposed to the gap? If exposed, is it possible that is your moisture source? Or possibly from other parts of the basement if your wall wasn't fully sealed up yet? I spray foamed the bottom of the foam panels so there is an insignificant amount, if and concrete showing. The bottom 4' of the insulation doesn't seem to sweat. Just the part of the foundation close to and above grade.
Hi Mike, can you elaborate on the floor insulation approaches? Wouldn't adding another vapor barrier above the floor be a problem in that scenario? If there is a vapor barrier already, then presumably the concrete would be dry as it is protected from below and able to try into the air above.
And, the assembly shown in that image includes a 6 mil poly barrier for radon gas protection, but worth noting is that 2 inches is about the thickness when EPS rigid insulation acts as a vapor barrier anyway. I have an older built home that we just bought about a year ago. I recently built a 5th bedroom in the basement, and discovered that behind the wallboard, there was no insulation at all, just bare concrete.
I think I followed your advise and glued 2 inch ridgid board directly to the concrete, spray foamed the top gaps between foam amd joists and rim board and tuck taped all seams. I then layed down some barricade subfloor panels thoughout the room, then built a 2x4 wall snug up against the ridgid board on top of the subfloor, and insulated these cavities with roxul insulation. I then drywalled over that and primed and painted with latex paint. My question is, would that be a correct way of doing this?
Also I am now about to start the rest of the basement, should I continue this way? Or would I be far better off just to get a spray foam guy in to spray directly on the concrete?
And the flooring in the rest of the basement is also a concern. A had debated laying down some dimpled membrane with plywood as the barricade flooring is a bit if a pain to install in a floor that wasn't poured very well. Any suggestions? What you did on the walls sounds about right, so if you're happy with the price and work load I wouldn't necessarily switch to spray foam unless you're sick of doing the work because it will likely cost you more. If you do go with spray foam, see our page here to choose the best brand -.
New HFO blowing agents for spray foam will make it over 1, times less harmful to the climate. The only thing that concerns me is the barricade floor. I am no suggesting you lift what you did, but I may add a step - a layer of 6 mil poly ahead of time. If you don't have a vapour barrier below the slab which was not a practice done in then the concrete will constantly be wicking moisture from the groudn below.
So moisture could migrate through the seams between each of those panels and cause the OSB to deteriorate over time. Again, I'm not suggesting you lift your existing floor, but this would be a little upgrade that may extend the life, and it means you aren't switching building materials and causing a change in floor level. One more question. If I stick with the method above no vapour varier, and insulating the wall after the foam is glued to the concrete wall , what is your recommendation, can I get away with EPS?
Hi, thanks for this awesome article. I just wanted to make sure I understand what you are recommending correctly. If I use mineral wool rigid board insulation e. Comfortboard instead of XPS or EPS panels right against the concrete, would it be appropriate to put in vapour barrier polyethylene on the interior side of the Comfortboard stapled to the exterior of the stud wall , and then fill in the stud wall with mineral wool bats and finish with drywall?
I ask this because it seems to me that mineral wool is completely permeable to moisture unlike the foam products , so it would seem important to compensate for that by adding in a vapour barrier. I live in Edmonton, Canada, so our winters are cold. Hi Mike, my home has framing on the exterior walls of the basement.
I am about to start finishing the basement and I noticed there is no polyethylene between the bottom plates and the concrete. The bottom plate is also regular SPF. Not pressure treated. What should I do? Do I need to rip out the walls and start over? Hi Frank. Tough call, it's best to keep a moisture barrier between them but I imagine that will be a lot of work. Is there any signs of water damage on the floor from previous flooding?
Is it humid? Most basement finishing is done exactly like that so I'm reluctant to say "yeah rip them out". So I assume there is no vapor barrier against the concrete behind the stud wall either? That's where it's best to have it. If you leave it as is just be sure not to put a vapor barrier after the studs to seal it in with the wet concrete, as you likely read above, that's the biggest and most common mistake ever made in basements.
If there was anyway to pry the wall up a bit and slip some plastic under it that wouldn't be a bad addition, but really I'd base it on the humidity level and chance of flooding. And is it a new house with a vapor barrier under the slab? Hi Mike, thank you for your quick reply. The house was built in No idea if there is a vapor barrier under the slab but I will try to find out.
There is no sign of humidity or water damage in the basement. Also no chance of flooding as we are on a hill. I will check if there is a vapor barrier behind the wall against the concrete. Who knows, maybe I will be lucky! I'm adding a 2 piece washroom in a finished basement. The entire basement was finished with tar paper on foundation wall 2 by 2 framing with fiberglass insulation, vapour barrier and drywall.
I have gutted the room down to foundation wall and am planning to use 2" rigid glued to wall 2 by 4 framing with roxul and drywall. Is this best approach given that the rest of the basement was done incorrectly according to this article? My 6" thick basement slab is not insulated at all, only 7" of gravel underneath, straight onto sandy soil. A possible issue I may have though is that if my basement floor ever get flooded again got exactly 2" of water onto it 2 years ago due to the 5' street ditch being jammed with ice and snow , the entire insulation and subfloor may end up floating on water.
I was thinking of leveling the existing rough concrete floor to level it so as to not have air gaps below the foam boards.
Would that work? If you've had flooding before I'd install a sump pump before insulating your basement floor.
I don't see why you'd need to pour concrete, if you cut the EPS to fit fairly well and even spray foam them at the walls then they wouldn't need to be set in concrete not to move. If it's just stone instead of concrete you can better ensure the EPS won't get saturated with water as it will have better drainage to your sump pump. And it's really easy to level using a transit, which you can rent if you don't have one not many people have one. Here is our page on how to mitigate radon gas in basements , that will help you do that properly if you're doing it yourself.
You need to be sure to have a passive or active radon stack and vent it out of the house, out the rim joists is a great place, that way you can see it easily. Sometimes they get frost build up and you can clear it. If its on your roof you'll never know if it's blocked. Thank you, Mike for this article. We get a few hearty freezes a year. We do not have water in the basement, nor french drains i'm guessing. Years ago we also halfheartedly painted the walls with limeprime.
I was thinking of just staining and sealing the concrete. I am mold sensitive and mildly chem as well. As long as we keep the dehumidifier going i'm currently just fine but without it I am not. It's not musty at all with it and only very mildly without. We have large galvanized steel hvac ducts running below floor joists. Can we hide these in dry wall too and do we need to insulate to prevent mold?
Is it risky to finish the ceiling? My husband already installed interior wall steel studs and mold resistant drywall, just in case. What is the best move for exterior walls? Can you advise what would be most ideal for finishing the walls? We are willing to pay to do it right but the sky is not the limit on what we can spend. But lots of sweat equity on hand. We want to be eco-friendly. If we divide the finished space into 3 rooms plus bath, would each space require a dehumidifier or would leaving the doors open so they are all connect suffice.
Finally, do we need to treat the air? Our radon level hovers around 1. Thank you so much, Mike, for what you do and for sharing your expertise. I have seen people using house wrap against the wall before building the stud walls and installing insulation. There point theybsaid was to prevent the water yet let it breathe. Does this make sense? Hey, I am redoing my basement soon and had a couple questions.
I live near Chicago, which if I looked correctly puts me in climate zone 5. The house was built in the 60s so I doubt theres exterior barrier. I have a cinder block wall basement that currently has wood paneling covering it. There appears to be some water damage from when the house was empty do to forclosure, but we havent opened the panels yet to investigate further, so obviously I'll know more on condition after. I was thinking about putting some vapour barrier paint on the block walls then follow it up with possibly with some 2" EPS glued to the wall with a stud wall built after with drywall.
I was just curious on possible recomendations based on the info given. Sign Up to Comment. What you noticed points directly at what the problem is, which is the vapour barrier.
When you removed it, the moisture was able to escape and be managed easily by a dehumidifier or ventilation equipment your HRV. And then when you put the vapour barrier back up the condensation formed again. That means the wall is wet, and the vapour barrier is preventing it from drying. Despite it being allowed and usually insisted upon , putting vapour barriers on basement walls does nothing good, but it does a lot of harm. You can read more here —. Why are Basements Moldy?
The short story is that concrete is wet and dirt is wet, so if you put plastic against it, condensation will form. Installing polyethylene vapour barriers is the worst thing you can do in a basement. Putting organic materials such as wood against a wet concrete wall, then covering it with a sheet of plastic will only ever result in one thing — wet, rotten walls. Why this was allowed to go on as long as it did and still does is a mystery.
We can help with a few solutions, I just have a few questions first -. Are the wood studs directly against the concrete or is there rigid foam insulation behind the stud wall? If not, is there anything there like a tar paper or house wrap? Is there a black tar spray on the exterior of the foundation? Is there any membrane on the exterior as well? It would look like this waterproofing basement dimple membrane.
Also, what is your climate zone or closest major city? That isn't a big surprise since MDF is a heavily processed wood product very susceptible to moisture damage , so it can be a bit of a canary in the coal mine in terms of basement moisture damage since it will show damage quicker than solid wood and most other process wood finishing materials. But the biggest problem you have, and that all basements have, is a vapour barrier sealing organic materials in with wet concrete.
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