The best way to insulate under a slab on grade concrete foundation is with eps rigid foam insulation.
Best insulation under concrete floor.
This allows an area for insulation and fill material under the slab.
The good news is that all the mentioned products can be found right here at insulation shop.
Best seller owens corning foamular 250 2 in.
Foamular 250 foam board.
Check for level frequently as you go.
Many builders will baulk at this figure it was not long ago that installing 50mm of insulation in the floor was considered fairly advanced.
In this scenario a rigid foam insulation is usual and as you d want the same u value in the roof we need the same thickness of insulation 180mm.
Insulation is laid on the concrete and covered with a screed.
They keep the depth of the floor construction down meaning less excavation and are easily handled and laid to quickly insulate large areas.
Foamular does not absorb water like other types of foam board which makes it ideal for below grade and under slab installations.
Many builders bevel the top of the vertical insulation so that none of the rigid foam is visible after the concrete slab is placed.
However i think by far the best option is one that offers complete insulation from the ground.
Another option for insulating your concrete floor are some more flexible materials such as knauf rock wool insulation slabs or rockwool insulation slabs which also offer a level of sound insulation apart from known as being great and versatile insulators.
Always measure for an exact fit so as not to compress the insulation which can compromise its performance.
Adding insulation under the concrete floor requires the same skill set and equipment as forming and pouring the concrete slab.
A concrete floor is an excellent solution for a high performing home.
In cold climates climate zones 4 and higher it s important to install vertical insulation on the interior side of the stemwall all the way down to the footing.
Strips should be about 12 1 2 inches wide.
Foamular provides r 5 per inch of thickness winter and summer.
Home depot does sell the right solution for residential concrete slab insulation.
Maxraft offer just this type of complete solution and i caught up with quantity surveyor craig lonsdale from queenstown to find out more about the maxraft system.
There will be a damp proof membrane under the insulation and possibly a second membrane on top depending on the type of screed.
Lightweight rigid polyisocyanurate pir foam insulation boards such as those manufactured by celotex are among the most thermally efficient commonly available insulation materials.
Step 1 excavate the area under the slab to 12 inches below the planned level of the top of the slab.
R 10 scored squared edge insulation sheathing.
6 fit 1 1 2 inch thick rigid foam insulation between the sleepers.
Get free shipping on qualified under slab foam board insulation or buy online pick up in store today in the building materials department.