The perimeter walls were already in place when this subflooring was added. So it made all electrical outlets on the perimeter walls lower that normal.
I started questionning the reasons for raising the subfloor this way. Additionnaly, I have discovered that the last 24 inches of the concrete foundation behind the perimeter walls at the slab level had not been insulated.
There is an approximate 4 inch space between the walls and the concrete foundation. So now, I am thinking of removing the gypse walls and insulate properly. My problem is to determine whether I should pull the entire subflooring structure including the 2 X 4, insulating appropriately and then building on top or, removing part of the subfloor such as the engineer wood and veneer and insulating between the 2 X 4 with EPS or XPS foam panels.
I am thinking that leaving the existing 2 X 4 against the slab might create some other issues in the long run since in direct contact with the slab. What is your opinion? I live in Calgary and want to upgrade insulation on my home.
The basement has lino on top of concrete. I'm wondering how to insulate that floor. Can I avoid a subfloor and still get high R value? What materials would you suggest? You can imagine that living here, most people will advise a minimal amount and say that I won't get a return on investment. I find their response discouraging, and I keep looking since there are other values at play. Thank you. I really appreciate your opinion. Sign Up to Comment. Here is a page that details it even more-.
How much insulation a basement needs. Heat always moves from warm to cold, so as long as the ground below your slab is cooler than your slab which it would be by about 15 degrees Celsius in your case you will be feeding heat into the ground.
Your basement should be designed by a professional of course, but we would recommend EPS foam, at least 4 inches, better would be 6 or 8 inches if you can, but not more than that. Below is a thermal model of what a floor would like in a climate similar to yours. The image on the left is uninsulated, and you can see by the extended colour gradient below the concrete from warm to cold is evident to a depth of many feet, while in the images with insulated floors you can see that much more heat is contained by the insulation.
Also worth noting is the light red colour of the uninsulated floor which indicates a cooler temperature that the white-coloured insulated floors, which is less comfortable for occupants. There are also insulated slab on grade form kits for purchase where the engineering is all done and the foam acts as the forms, so there are no wooden forms to assemble and disassemble after concrete is poured.
Drop us a line at [email protected] if you want more information or a quote. That is a common question, and a hot topic that often brings dissagreement, but we like that though! So much so that we have a page highlighting the pros and cons, check it out -. But to address your questions specifically, I've included your questions in the response to make it easier for both of us -. Cost - I know a slab is cheaper but having a basement that we can finish allows for a smaller footprint with less walls and roof material.
Is there a big difference in cost? We have typically found above-grade walls to be a more affordable building option, but no, it is not a huge difference. A basement will result in a much higher excavation cost to begin with, but also, concrete is a more expensive structural material compared to wood, so an above grade wall assembly can usually achieve a higher performance level for a lower cost since you can use wood as the structure.
Yes, you will have a greater amount of above grade wall to build, but as mentioned, that can cost less than the same amount of below grade wall. Cement manufacturing emits a significant amount of greenhouse gases, and sand that is suitable for concrete production is becoming an increasingly scarce global resource, where wood is renewable.
As for durability — basements walls cannot dry to the exterior, so more caution must be taken in designing and building walls below grade. If your house is above grade and not in a flood plain, you will never have to worry about it flooding. Access for mechanical - I can't get my head around having to embed drains, plumbing, electrical, etc in concrete as opposed to putting it under floor.
Not to mention running ducting for ERV. Is this a valid concern? What if there is a leak in the drains, how would you ever know? More than being a valid concern is the part about wrapping your head around it, so that's all relative. I have no problem with embedding the infrastructure in the concrete but I would have a hard time wrapping my head around the idea of digging a hole in the ground to live in it when I could be living above grade.
It's more a matter of what you're used to, if you go to California for example, you'd have a hard time finding a basement because they build all their houses on slabs and don't give it a second thought. Where concern is valid is - you cannot change plumbing in the future so you need to be sure you are happy with the house layout to begin with.
So hire a licensed plumber and don't worry. As for the water feeds and electrical lines, they should be put into conduits a sleeve , so if there ever was an issue you can pull them out and replace them. However, the insulation is not perfect and the slab is not insulated.
Given the initial results, I decided to thermally isolate the basement by insulating the heating ducts and the basement ceiling with R fiberglass insulation.
As soon as I did so, the average basement temperatures dropped about 3 o F and showed much less variance during the day. The basement is now hovering around 57 o F and I heat it independently, with a small natural gas, stand alone stove when I want it warmer.
Next winter's data should show a slight additional savings from insulating the ceiling. If you care to think about what the heat losses are and how they flow through your walls, here's a start:. As an example, consider a square foot of concrete 6" thick, with an R value of 0. If you hold the inside of the concrete at 60 o F and the outside at 30 o F, the heat loss is:. How many square feet of uninsulated foundation wall do you have? Site customized and supported by Spectral Fusion Designs Sheriff Basement Insulation.
As you plan out finishing your basement, you also need to think about the cost of spray foam insulation to make it a comfortable space. Insulating your basement consists of a combination of three areas — the basement walls, the basement ceiling, and the rim joist. RetroFoam of Michigan has more than 17 years of experience insulating homes across the lower peninsula and the greater Toledo area with spray and injection foam insulation.
We know using spray foam insulation is the best way to create the air seal you need for your basement. We want to educate every homeowner as much as possible, so in this article we'll talk about the cost, but also the factors that go into it. The size of the basement and what areas are to be insulated is the top factor when determining the cost to insulate the space. Another factor in determining the cost is the material used in the installation process.
In most cases, spray foam insulation will be used in the basement walls unless the drywall has already been put up. While not as common, in that case, injection foam would be used instead. This can also factor into the cost because closed cell tends to be more expensive than open cell spray foam. 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.
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