Slab floor / Discussions

How do you run ducts for heating and cooling with slab on grade construction?

...slab on grade floor, would be a heated floor. here is out page all about different under floor radiant heating systems. Cooling is a different matter, some people put in air-to-air heat pumps cooling, and radiant cooling is something of a contentious topic but can work, as long as you don't 'over' cool the floor to the...

Posted by Kurt Piemonte April 24, 2025 Slab on Grade 1 response

What are the best below grade drainage layers for a slab on grade foundation?

...slab on grade foundation starts with building it on a suitable base that won't heave and that has sufficient drainage. First I would read this page - How to build a slab on grade foundation: the Ecohome step by step guide We can advise you on the best practices for building a slab on grade, but you would still need a d...

Posted by stephan prystanski April 7, 2025 Slab on Grade 1 response

What's the ideal concrete thickness for concrete slab floors?

...floor designed to harness thermal mass advantages. Slab Foundation: This concrete floor is not intended as a structural slab foundation. Should I directly design it as a traditional slab foundation? In this case, the thickness would be around 4-to-6 inches. Floor Sandwich Structure: I'd like to understand how the layer...

Posted by Abdulkadir Al-Jazari March 28, 2025 Basements

Can you raise a garage floor?

...floor is almost back alley level, it has retention wall,  and inside about 6 inches height from the slab. We like to raise it at least 4 inches! Is it possible?  If so, how?  Thank you in advance.  That would be a very tricky and expensive undertaking, have you considered pouring an additional concrete floor on top to ...

Posted by Anwar Chowdhury Jan. 3, 2021 Concept and design 2 responses

What's cheaper for total building costs, slab on grade or basement?

...floor, and means loss of interior space as well as the cost of building stairs. Basically its like this – complexity costs money. The more simple you design it the cheaper it will be, and slabs are  more simple than basements.  Personally you couldn’t really talk me into building a basement unless there was really no o...

Posted by tony wolff Dec. 24, 2020 Foundations and Basements 1 response

What is the best way to install slab on grade insulation?

...slab EPS foam insulation is nothing compared to the labor required to switch to an entirely different method of insulating. I would first point you to this page -  Slab on grade technical guide We have other pages on slab construction as well that are worth looking at, you can find them if you enter slab on grade in th...

Posted by paul fowler Aug. 26, 2021 Slab on Grade 3 responses

What thickness of insulation and concrete do you recommend in a floating slab?

...floor system for a new build in Quebec. The contractor will build a floating slab with footings. The contractor is suggesting 2 inches of insulation and 3 inches of concrete, which seems too little base on what I have read. What do you recommend the thickness to be for the insulation and the concrete for the slab and r...

Posted by Marc-Andre Roy April 21, 2021 Slab on Grade 3 responses

How much perimeter skirt insulation should go around a concrete slab?

...slab and subfloor above.  On top of the slab will be a wood subfloor web-truss system where the electric & plumbing & hydronic floor heating panels w/ PEX tubing will be located - as these will not be buried in the concrete (subfloor space height around 18" from top of slab up to bottom of flooring). Here's my ...

Posted by Insinuendo Insinuendo Aug. 5, 2022 Slab on Grade 3 responses

Is an engineered slab on grade as good as a foundation footing?

...slab on grade so that there is no shifting with frost. Is this not the case anymore. Is a slab on grade the best practice? An engineered slab on grade that has been designed for it's climate is as reliable at preventing frost heave as a foundation and footing. We are creatures of habit, and we have always *known* that ...

Posted by Jeff Ryan Feb. 15, 2022 Foundations and Basements 1 response

Can you replace an old slab foundation with an air heated slab?

...slab on grade house and pour a new slab under it, unless of course I’m missing something here. The raft slab insulated slab on grade kit with the air heated radiant floors is intended for new home construction, though you could raise a house and build a basement with one.  So – on the off chance you have a crawlspace a...

Posted by Mike Molloy Nov. 7, 2019 Slab on Grade 1 response

What is the optimal setup for mechanical systems for slab on grade?

...slab on grade home. I definitely want a hydronic in floor heat system, along with a heat pump. With the absence of central ductwork, where do I put the ERV? Would it make sense to run a house wide plenum for the ERV alone? And if that's the case, would it be more efficient to hook the heat pump in to the ducting, rathe...

Posted by Dave Nuttall July 6, 2019 Mechanical systems 1 response

Would you recommend Legalett over water radiant floor heat for a backyard studio in Toronto?

...floor, below is a link to an installation video as well as a few other resources on slabs. Legalett Solar Air Heated Slab on Grade installation video Slab on Grade Prefabricated Insulation Form Kit  Air heated floor Thickened-edge slab-on-grade technical guide

Posted by Christine Pountney May 2, 2019 Delivery: radiant, forced-air and decentralized 1 response

Do I need to insulate under the footings of a frost protected shallow foundation?

...slab to ensure durability: The AFI (air freeze index), how much insulation encases the slab, the soil conditions, and whether or not the slab will be heated. The best way to ensure that a FPSF (Frost-protected shallow foundation or slab-on-grade) doesn’t heave would be to have it modelled for your specific climate by a...

Posted by Jon Piana April 15, 2019 Slab on Grade 1 response

What should I look for if I want to buy a slab on grade house?

...Slabs also tend to be closer to the ground that a standard foundation, so I would inspect the bottom of the siding to see if there is moisture damage.  I would also ask for any building details that may be available; and if it has a radiant floor I would personally want to see the utility bills to know what a winters w...

Posted by terry northcott March 25, 2019 Slab on Grade 1 response

What is the best way to heat an off grid home?

...slab hasn’t been decided on yet, check back with us soon as we will be starting construction on our next demo house in about 3 weeks (September, 2018), which will have solar-heated air panels feeding air tubes in the slab floor. Solar air heating panels are a lot less hassle and risk than solar water heating panels, an...

Posted by Michelle Nason Aug. 8, 2018 Off-grid and Net-Zero Housing 3 responses

Does insulating a slab on grade make the building less stable?

...floor heating. Since the slab need to be insulated all around, a builder told me he would not recommend that due to the entire weight of the building resting on the insulation sandwiched between the ground and the slab. What do you think?  A Slab on Grade needs to be built correctly, but no, Insulation under a slab flo...

Posted by Nicolas Jalbert May 28, 2018 Slab on Grade 1 response