Table of Contents
How thick should foam be under concrete slab?
A 2-inch layer of rigid foam insulation is forty times more efficient at trapping heat than concrete alone.
What insulation should I use under concrete?
Insulating a solid ground floor below the ground bearing concrete slab can be done using either PIR insulation boards or EPS insulation boards. EPS can be a cost-effective alternative to PIR for floor insulation, and the same thermal performance can be achieved with increased thickness.
Should you put foam under concrete?
Concrete contractors learned that a layer of poly helps to keep a slab dry, because it stops upward vapor diffusion from the soil. The foam layer isolates the room-temperature slab from the cold soil under the slab.
Can you put Styrofoam under concrete?
Putting styrofoam under the slab is fairly common here. If the base is preped and tamped properly, and the correct concrete and wire is used, you will crack no more or less than you would without the foam. use plastic VP under the foam, and you will end up with a nice warm dry slab, GMOD.
Why do they put foam under concrete?
This is to stabilise the slab beneath the building. This results in more concrete being used, as well as an increase in labour to prepare the site for the concrete pour.
How do you insulate a poured concrete slab?
Place 2-inch thick pieces of rigid Styrofoam insulation on top of the plastic sheeting. Place the insulation edge to edge, using duct or other construction tape to hold the insulation together. When completed, the entire slab area has a cover of rigid sheets of Styrofoam.
Why do they put Styrofoam under concrete?
How do you insulate a concrete floor before pouring?
- Excavate the area under the slab to 12 inches below the planned level of the top of the slab.
- Place 4 inches of gravel in the excavation.
- Lay a layer of 6 mm plastic across the floor.
- Place 2-inch thick pieces of rigid Styrofoam insulation on top of the plastic sheeting.
- Add insulation on the inside edges of the form.
What kind of foam goes under concrete slab?
The most common insulation materials for use under a concrete slab are extruded polystyrene (XPS) and expanded polystyrene (EPS). Of these two materials, green builders prefer EPS, because EPS is manufactured with a more environmentally benign blowing agent than XPS.
What kind of foam goes under slab?
Two of the rigid foam insulations most commonly used below grade and under slabs are expanded polystyrene (EPS) and extruded polystyrene (XPS). Although both are closed cell insulations, they perform very differently over the long term.
Is it worth insulating a concrete floor?
Insulating a concrete floor. When building or renovating a new space, insulation should always be considered. From preventing damp to reducing heat loss and aiding with noise dampening, below-grade insulation is always important.
Do I need a vapor barrier under my concrete slab?
The single most important reason you should use a high-performance vapor barrier is to protect the expensive floor covering in your building. Liquid water below the slab can diffuse through the slab as vapor, then condense under the flooring, which can emulsify some adhesive and destroy the floor covering.
How much insulation does a 4 ” concrete slab need?
A 4″ slab contributes about 50 psf of load; add a 40lb live load and you’re still below 1 pound per square inch. The compression curve for foam plastic is usually pretty straight, so insulation rated at 15 psi would compress somewhere in the neighborhood of 0.015 of its thickness. For 3″ foam, that’s less than 1/16″.
Where can I find the PSI of insulation?
The k value can be found by consulting the insulation manufacturer. One EPS insulation brand available throughout the U.S. has k values ranging from 360 to 1860 psi for one inch of insulation thickness. The specific value depends on the product type selected.
Which is better rigid foam or concrete floor insulation?
As much as 10% of the heat in a home – and therefore 10% of your energy bill – escapes from the floor. A 2-inch layer of rigid foam insulation is forty times more efficient at trapping heat than concrete alone. Although rigid foam can be expensive at the outset, the savings over the next few decades will far outweigh it.
What should the pressure be on EPS insulation?
Pressure on EPS = (P/8)√(K/D) = 8000/8 √(180 / 52,480,818) = 1.85 psi. The k value can be found by consulting the insulation manufacturer. One EPS insulation brand available throughout the U.S. has k values ranging from 360 to 1860 psi for one inch of insulation thickness.