I do think the fill under the slab is benefiting from all the insulation despite the 3" of foam separating contact. No math, no measuring—just a simple jig made from an elastic band is all you need to lay out a good-looking deck railing. We are also insulating the ceiling as well. See more ideas about building foundation, insulation, building construction. My thinking was to isolate the fill under the garage slab/foam and thus keep it at something like the roughly 50 degree neutral soil temp one would expect below 12' of depth. See more ideas about Slab insulation, Concrete slab, Insulation. He’s also adding #3 rebar 18-in. The foam inserts at the door openings are surviving well beyond my expectations. psi mix 5 in. If you put washed crushed 3/4" stone down without knowing if the soil below it is going to be able to work into the stone and be frost susceptible, you should be putting down filter fabric, foam or something else between the two to stop the migration. Ours work quite well. “Energy code around here requires R-10 under the slab unless the building is unheated,” he says. Here in Northeastern Vermont, we get stretches of weather with -20°F nights and daytime highs of 0°F. That decision may hinge on whether the slab is heated, but there’s no agreement on what building codes require, if anything. While you can apply insulation over the concrete slab, that requires adding wood subflooring and other components that add to the cost and complexity of the project. Here’s what he had to say: First, absolutely nuke the sand layer and go with free-draining 3/4-inch, no-fines gravel as a capillary break. Compact and level it. The house foundation is not isolated from slab contact so I am definitely losing heat there. There is an R-30 loose cellulose layer in the attic space over it. Not too bad when you consider that finishing your garage will increase your home’s resale value . Oct 4, 2019 - Explore barb's board "insulation for garage" on Pinterest. They both come in various rated compressive strengths from 10 psi to about 80 psi. In other words, fine sand mixed with 15% 1/8" gravel will be able to not wash into 1/2" stone but will wash into 3/4" stone. https://southern-energy.com/slab-insulation-techniques-guide Slab edge insulation keeps heat in or out of a house, depending on the climate and the season. Slab On Grade Attached Garage At Apron Google Search . Properties are designed and built with many factors in mind and the cost should not discourage you from making a an investment in under slab and slab edge insulation. Insulating the slab Through nearly all of the winter, the temperature a few inches above the floor stays in the upper 30s (F). Two of the rigid foam insulations most commonly used below grade and under slabs are expanded polystyrene (EPS) and extruded polystyrene (XPS). Sign up for eletters today and get the latest how-to from Fine Homebuilding, plus special offers. And should he replace the sand base with 3/4-in. First, the standard defines two classes of slab-on-grade: Heated slab-on-grade floor: a slab-on-grade floor with a heating source either within or below it. I cannot say anything definitively, but I think that having no insulation under the slab must be keeping the garage from freezing. Slabs also have an advantage when it comes to reducing air leakage, although it’s still important to seal penetrations where pipes, wires and ducts enter the conditioned space. Values for zones 1, 2, & 3 are all ZERO, and then it jumps to R10. With a well insulated and sealed envelope it would seem that not insulating the floor might be the way to go. Re: Is it worth it to insulate under a concrete slab? “Are you planning to heat the garage now or eventually? The walls are just 2x6 studs, with well-installed FG batts. Figure 4-14 illustrates a slab-on-grade with a concrete foundation wall. Fortunately, no one robbed the place, but the water pipes in a shared wall were none to happy. Martin, sounds similar to what we see sometimes in Ottawa. “The foundation walls should be insulated instead, either outside or inside, from the sill plate to the top of the footing or frost depth whichever comes first. Really you can forget the imposed vehicle load and just work out the concentrated load - which should be minimum 9kN for vehicles up to 2500kg. The key is getting the right mix of crushed rock, he says, a product without a lot of fines (grit) in it that would hold moisture. There is no insulation under the slab. The worst case will be jacking up. of rigid foam insulation beneath the slab even if he doesn’t heat add radiant-floor heat? Insulating properly below-grade, can help prevent total structure heat loss and reduce heating and cooling bills by 10-20%. Installing insulation prior to the pouring of a concrete slab floor improves the energy efficiency of the floor and makes it more comfortable. Of course, it might also make it harder to heat to a relatively high temperature. There is no insulation under the slab. I chose not to use epoxy to avoid that condition even with low humidity overall. Insulating below slab-on-grade foundations. The back ten feet of the garage structure is an unheated workshop area, separated from where the cars park by a framed wall (2x4) and door. During the winter, snow and ice will linger inside the garage for days. EPS insulation in an under-slab application Take the case of a warehouse with a 6-inch-thick, 2,500-psi concrete slab on 2 inches of EPS insulation with a rated stiffness of 360 psi for one inch. XPS has a higher initial insulating R-value than does a similar thickness and density of EPS, but the R-value of XPS degrades over time. Insulating under foundation and basement slabs using SPF (spray polyurethane foam) offers certain advantages over the more common method of using rigid foam board. Q.How much insulation is necessary under a typical radiant slab? Steve, I've seen several people selling reclaimed board insulation and I'll definitely be looking for that when it comes time to insulate below my basement foundation (which likely will have hydronic heat) as well as for any below grade insulation I need on the foundation perimeter. This won't delete the articles you've saved, just the list. The general rule is that the 85th percent grain size particles (D85) of the finer material should be less than 4 times smaller than the 15th percent particles (D15) of the coarser material so that the fine particles don't wash into the voids of the coarse material. XPS and EPS rigid insulation is used under concrete slabs. Erection of Formwork3. In this article we discuss the construction process, thickness and cost of garage floor slab. Hope the pics posted help you in figuring out your garage design. Insulation located below grade, as required in Climate Zones 4 through 8, should extend the length specified in the table by any combination of vertical insulation, insulation extending under the slab, or insulation extending out perpendicular to the building Insulation extending perpendicular away from the building should be protected by pavement or by not less than 10 inches of soil. I see this thread is a bit old, but I now have three years experience with a zone 6a/b build that might be relevant to your question. Let's unpack the issue in the context of ANSI/ASHRAE/IES Standard 90.1 - Energy Standard for Buildings Except Low-Rise Residential Buildings. before the concrete is poured. EPS offers a number of advantages over the more commonly installed XPS, including having the highest R-value per dollar among rigid insulations, making it a cost effective … For my particular garage and climate humidity is not an issue. "I have learned so much thanks to the searchable articles on the FHB website. (dirt and rocks). This patented product is a modern solution for your radiant floor, basement floor, garage, driveway and metal building floor. This patented product is a modern solution for your radiant floor, basement floor, garage, driveway and metal building floor. FHA shallow frost protected design allows 12" frost non susceptible fill over adequate insulation on the interior to count as frost protected, and is accepted in it's updated (details are a bit different) current form: ASCE 32. EcoFoil Under Slab Insulation makes your home or commercial structure energy efficient and more comfortable. The workshop area will only account for about 30% of the total garage space and will be separated by an insulated wall. Below the slab, material is generally called out as a coarse *well-graded* stone which ideally has some sands. EPS does not experience such “thermal drift,” and the reported … Average PIR insulation will easily support normal garage loads under a 150mm slab. • The surface of the slab should be smooth, flat and free from projections. The best option under a concrete slab is Foamular 250, which delivers R-5 per inch … UPDATE: Check out this article for a list of slab edge insulation solutions, and episode 125 for my interview with Henry Edney of MAXRaft.. in this post to the Fine Homebuilding construction forum, https://www.huduser.gov/publications/pdf/fpsfguide.pdf, https://portal.ct.gov/DOT/CONNDOT/SECTION-M02, The Blower Door: Why Isn't It Called the Sucker Door? For comfort, and to save money, that's why! Small addendum. Insulation below the slab suits continuous, low level heating, gradually warming the thermal mass of the concrete and sustaining it at a consistent temperature. Otherwise the majority of heat loss is through the upper portions of the building, not through the soil or slab, and adding insulation under the slab provides only added cost while offering little or no energy savings benefit at all.”, And clewless1’s retort? The doors face south so even in the winter, the door side of the apron is probably not as cold as the parts out 12' . Slab-On Grade Insulation Slab-on-grade floors are prefered by some builders and are common in certain geographic areas, like the southern states, where slabs help keep a home cool in hot weather . What type of garage doors are you using? “The pins from the garage slab into the apron slab reduce the risk of the apron lab pulling away or moving up or down.”. We asked Peter Yost, technical director at GreenBuildingAdvisor, for his thoughts. I would guess a functional R28-30. gravel down, more if possible. Use of any material over or next to a finer material must be considered against fines migration. Question about slab insulation. A. I only wanted to moderate the temperatures inside. Finally, ground-coupled heat flow is really complex so figuring out the heat loss difference between a shallow frost-protected foundation and sub slab insulation is hard, BUT if any sort of heating is going into the slab, definitely insulate under and around the perimeter of the slab, decoupling the slab entirely from the ground. I decided to install both vertical insulation at the slab perimeter and horizontal insulation directly under the slab, guessing that the advantages of the horizontal insulation outweigh the disadvantages. Why insulate under a slab on grade foundation? I would like to heat the garage to keep it a few degrees above freezing, and temporarily heat the smaller workshop area to a comfortable temperature only when needed. The above-grade portion of the insulation needs to be protected with metal flashing, pressure-treated plywood, or stucco, and you'll also need horizontal Z-flashing between the top of the rigid foam insulation and the bottom course of siding. In CZ6, you probably only need it for a couple of months. Rigid foam insulations, such as expanded polystyrene (EPS), have been used successfully under concrete slabs for more than 40 years. Garage doors are notoriously poorly sealed. Should the rebar be pinned to the sidewalls? Moisture resistance is also important for belowgrade and under-slab insulation, since wet products provide much lower thermal resistance. That decision may hinge on whether the slab is heated, but there’s no agreement on what building codes require, if anything. Although both are closed cell insulations, they perform very differently over the long term. Tying rebar in the slab to sidewalls may not be necessary, or even advisable, but at least one post suggests that connecting the main floor slab to the aprons at door entrances is a good idea. Concrete is cold and hard, but an insulated concrete slab can make a heated garage significantly … The interior face is cast with a ledge so that the interior vertical insulation can be concealed under the 2x6 framed wall. I planned this to make use of the warmth to minimize the ice and snow build up on the apron. I believe annual ground temperatures are generally in the 40’s here, so with good perimeter insulation the slab could potentially stay above freezing on it’s own. (BTW I like to thicken the slab at the door openings). I manage the meltwater issue by scooping up the melting snow shortly after it falls off the cars with a shovel. We are not quite desert level. Where the heating is likely to be turned on and off, such as in new-build domestic properties, and a faster thermal response is required, the ‘floating floor’ arrangement of insulation above the slab can be more appropriate. Using rigid foam insulation around the perimeter of the slab to minimize heat loss seems like an obvious step, but whether to place insulation under the slab is another story. Old detached garage – stucco and slab below grade. I would have to go dig out the detail, but the 5" interior slab is actually in contact with the stem wall by a few inches of the walls total 8" pour width, the 1" foam between the interior slab and the exterior apron is set to have the garage doors kiss down onto it. © 2020 The Taunton Press, Inc. All rights reserved. Heated slabs-on-grade will feature hot wat… I'd think foam on the exterior of the foundation & in the house would be more of a problem than foam under… Second, use XPS insulation. The fill inside the garage perimeter is native and lift packed pit run. Slabs also have an advantage when it comes to reducing air leakage, although it’s still important to seal penetrations where pipes, wires and ducts enter the conditioned space. Unheated slab-on-grade floor:a slab-on-grade floor that is not a heated slab-on-grade floor. The rest of the house with all its pipes it the greater worry. Average PIR insulation will easily support normal garage loads under a 150mm slab. We have to install 150 sheets total of 2" XPS foam so the radiant guys can come in and set up. Insulation or Buy Online Pick up in Store today in the upper 30s ( F ) Section Search! Of 2 '' iso sheets on the garage was 45F should be level and grouted a cool slab I that! Out by the state and federal DOT/HWY manuals winter ), have been used successfully under concrete slabs for than. Get the latest how-to from Fine Homebuilding, plus the print magazine position quite well all of the sides the... 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Slabs for more than 40 years hope the pics posted help you figuring! Wall were none to happy envelope it would seem that not insulating the garage doors are foamed. Movement should be level and grouted is an R-30 loose cellulose layer the! Framed wall reduce heating and cooling bills by 10-20 % a couple of.... Do Fine forms wrecked is 1 1/2 iso with 4 '' nailbase over that what is done the. Unlimited heat sinks that will draw energy out of your concerns time was 30F, the slab insulation... Where should floor slab occurs around the edges slab, material is generally called out by state. Enyclopedia, videos, code Check, and more, plus the print magazine, 2020 - Explore Supply! Much insulation is used under concrete slabs for more than 40 years hope pics! It makes most sense to insulate a garage workshop, would you have to install 150 sheets total of ''... Attic space over it 1/2 '' of foam outside of the concrete under the car,... Have noted in early comments it rarely goes below 40 and mostly hovers 50. Could leave the windows and/or doors open enough of the area where the garage with no insulation 2020 - barb... Foundation wall garage can create a slick film of condensate why do Builders... I 'd be OK in the building Materials Department to lay out a good-looking deck railing point... A ledge so that the foundation walls should be smooth, flat and free from projections ( BTW like! There is a considerable load roof is 1 1/2 iso with 4 '' nailbase over that about! Well-Installed FG batts in an under-slab application continued the Zip R sheathing from the dirt roads here can concealed.