Code Enforcement Costs Owner $3000 For Styrofoam Under Concrete Floor 

I'll bet the break-even is within 3 years. After all, 30% of heat loss is down, through the floor. Here's another situation. My small home (Canada snow belt) is electric baseboard heated. Adding an airtight inset to my open fireplace, and burning only from Friday eve until Monday morning weekly, some evenings, through the Christmas holidays, and a few extra days, cut my electrical bill in half. The $3,000 stove and install, paid for itself by halfway through year three. Spread out over the year, that's saving $100/month over (30 months=2.5yrs), or $1,200/year. And, never having to spend it again. This is really only viable if your winter wood costs less than the saving. I harvest my own free firewood.

There is so little heat loss through a slab floor, it’s not what you think at all. I’m a mason of 37 years

With styrofoam keeping the concrete off the cold damp ground, it helps keep the slab warmer and DRY I have styrofoam and plastic sheeting under my basement concrete I poured section by section myself in the 1930 Iowa farmhouse, and I can go down and walk around in the winter in my socks and the concrete is not cold or damp. Its a one-time cost and on a $300,000 or whatever this new house cost to build- another $3k is pocket change. @@DanielJohnson-ec8rk

I put R-100 insulation in my attic, I also added another inner wall to all my exterior walls which were plaster and lath and in poor condition, I added studs inside, 2" of Celotex, a plastic sheet, 1/2" CDX topped by sheetrock so I could hang heavy things on the walls anywhere and not have to locate studs too. So the 4" walls had blown in insulation, added 2" celotex at R-7.2/" and the walls are around R21 or so. I replaced all the single pane windows. I was getting sheets of ICE on the inside of my kitchen windows in winter, where my computer and desk are, it ALWAYS felt cold and drafty, turned out the draft was convection currents caused by the cold window glass. I had to have a 1500 watt space heater behind my chair all the time. I replaced the 3 windows with MI windows, double glass, argon, low E vinyl, immediately no more ice, and the space heater went in the trash, I saw an immediate reduction in my electric bill of about $50/mo The windows were around $179 each, I installed them myself, they paid for themselves in 2 years. Same story in the bedroom where I always had another space heater on low all night, replaced those 2 windows and that heater went in the trash too, that saved about $35/mo Since then I replaced the rest of the windows but its unknown the savings as doing so didnt eliminate any more space heaters-only had the 2. Buy last winter I replaced my 35 year old 80% efficient, 110k BTU Lennox Conservator G11-e furnace with a new Goodman 80k BTU 96% furnace and installed it myself, new better ducts and more central location along with a humidifier. I saw a reduction in the gas use last winter, this winter will tell me more. That 80% furnace took all its combustion air from the basement which pulled in cold air from every little crack, and when it was off, cold air would often spill down it's 5" flue. The Goodman takes all its air from outside with a 2" PVC, I also installed a damper to allow a small amount of fresh intake air from outside to mix in the return duct. @@slowfinger2

Could you explain how the ground conducts heat and when does it reach equilibrium.

@@marcwert2180 You're not getting a course in thermodynamics over the internet. Go to engineering school or consult an engineer in person.

​@@marcwert2180 Take a course in college on thermodynamics. Don't rely on anonymous stuff posted on the internet.

@@marcwert2180 The ground stays at a mostly constant temperature year round. That is sort of how ground-source heat pumps work. (State-change reactions like freezing also sink a lot of energy.) If you dump enough heat into the ground it may eventually reach equilibrium. But water can carry your heat away as it makes it way down to the ground water level as well.

@@marcwert2180 I can try to give you a brief explanation. Steven is quite correct,, it is a long and involved study. First, the only equilibrium will be the temperature of the soil,, or the temperature of the outside air. There will be no blend or very little,, those two are just heat sinks. They will suck you right down to those levels. Some of the high points. Concrete is a heat sponge. To raise the temperature of one cubic foot of concrete 1 degree F,, takes (inaccurate but the correct idea) 100 times more energy than raising the temp 1 F for a cubic foot of air. Tremendous variables even within that because how much water is contained within the air,, or concrete, or soils. The next concept is the temperature of the soils. You almost cannot change the temperature of the soils under the building. Yes, a warm house sitting on a patch of ground will loose heat to the soil,, but you will wait decades before you see any substantial change. Temp of the soils beneath the house I am sitting in, 6 feet down, is 52 to 54 F Air is easy to heat, water is not easy, concrete is harder yet, the soils under the house close to impossible. If you isolate the concrete slab,, concrete is not in contact with footings, soils, or outside air at any point,, I repeat, at any point. The slab will be at the temp and relative humidity of the air above it. 70F air? 70F concrete. If the slab is in contact with the soils. the slab temp will be 52 to 54F. If the slab is exposed to outside air,, and the air is 10F then the slab will be 10F or close to it. R values. R values measure the resistance to heat flow. Common fiberglass insulation,, 3.5 inches R-13, R-4 per inch. Now line that up with R-4 per inch and foam under the slab is similar,, a 2 inch thick foam will be about an R-8 BUT,,, wood is about R-1 per inch,,, Concrete R-.08,, 8/100ths per inch it takes 13 feet of concrete to equal the insulation of one inch of wood.,, annnnnd if there is a bit of water involved,,there always is with soils and concrete,, that 13 feet will be more like 20 feet of concrete equals one inch of wood... If your foam job under the slab is just a little bit careless,,, the toilet pipe sticking up through the slab.. If the concrete flows down and around the pipe to reach the soils under the house,, it is called a 'thermal bridge'. that less than one square foot of concrete in contact with the soil,, will conduct the water in the soil up into the slab,, and drain away the heat. one square foot of careless install will chill 400 or 500 square feet of floor. Keep in mind,, as Steven said,, this is just a thumb nail clipping,, sort of over view. The full subject is a years long university level,,, you can get your masters in thermodynamics. The case of a house? Easier to think about a swimming pool of water,, poke a hole with a nail,, the water leaks slowly,, punch a basket ball sized hole It will all drain out rapidly. And this is just discussing the heat loss to the the under lying soils or outside air.

How did it turn out? I'm thinking of doing my driveway but have only watched mikes videos too

Depends on the climate, very cold climates yes, hot ones no!

There’s no need to put styrofoam under a heated slab, it should be put around the outside of the foundation. I have a 1000’ feet of heat pex in my garage floor and the foam is on the outside perimeter. The heat only goes down 10”, and it’s why a mixing valve on a tankless coil is piped 10” below the outlet. The heat won’t convect farther down.

@@geneticdisorder1900ur wasting heat, the Styrofoam would save you money in the long run

​​@@geneticdisorder1900the proper term is conduction. Solids conduct heat. Fluids convect heat. And technically it's that it won't effectively conduct the heat beyond 10" but the heat does conduct much further than that.

@@ianbelletti6241 Last time I checked, there was fluid flowing fabulously through my tubes convecting heat into the pex tubes, which conducts heat into the cement, which conducts heat into the dirty dirt. And all that mass of dirty dirt, cement impregnated with small crussy crushed rock than convects heat up into the air, which in turn warms my garage. Except where the 4 roundy rubbers sit on the cement and the heat is transferred into those 4 roundy rubbers and anything else that is sitting, stored or thrown onto the concrete floor. So in short, we were both half right.

Without beneficial heat loss from the building to the soil below the slab, frost heaving soils will move an insulated slab. It will heave up at the edges. Prevent freezing, remove free water or replace the frost susceptible material and it can’t heave.

Umm it'd make more sense for hollow floors not cement floors

@@meyatetana2973 Actually insulation concrete floor is the best because you lose so much heat trough them. It just helps so much.

@@meyatetana2973 Do your research. Hot goes to cold, if the floor is cold then your furnace or whatever you have is constantly trying to warm that cold slab. that slab it coventing the heat into the earth instead of you. Over the lifetime of that house that $3000 will pay it back many many times over. Not to mention the comfort factor. in Ma the new energy standard for new and remodeled house is HERS 42 0 being the highest score possible you should see what it takes to get to that level. homes built in the 1950s would most likely score a rating between 120 and 130.

Also have to have a thermal break between the concrete wall and the slab, otherwise your slab is effectively uninsulated and the edges will be cold in the winter and accumulate condensation in the summer.

Do not use the pink, green, blue, yellow foam in the ground. This is XPS, junk. It absorbs and holds water. There goes your r-value. Use EPS or GPS. And apply proper drainage.

I have 80mm/3.5" of PIR here in the UK and if building again I would probably fit more like 120mm/5".

How’s it go ?

Can you really call that a slump. More like a slurry. If they add a little more water it will self level , lol.

@@bluecollar58 Hear ya. If the finisher hollers to roll in more water, ya turn it on and rev er 👆 up

Ditto.

I was required to tape the poly seams with a specific tape and caulk seal the poly to the perimeter vertical foundation. The foam sheets are also glued with the proper adhesive. The poly is never going to move - float up to the surface.

The issue is that the foam may in come cases isolate less heat. I'm from Canada and opted to not insulate my garage floor. The reason for this is the thermal mass (soil etc.) below my garage slab keeps the floor warm much longer than if I isolated my floor from the thermal mass below using insulation. Night and day difference from my buddy who has his insulated, I think I made the right choice.

Entitled ignorance. You so proud.

Water Saver..

All that is true... I am from a nordic country where code is strict and adds 50k worth of cost to an otherwise simple home. Its a slippery slope once they start making up laws, it never ends. The end result is these very efficient new builds that no working man can afford, resulting in a housing crisis. So be carefull what you wish for. America should be about freedom to make your own choices. We've lost our way here

@@garage3022 Seems to me that codes should be about technical standards, structural adequateness, safety and that sort of purely technical requirements. Things like energy efficiency, handicap access and such should be recommendations and if done right, tied to tax credits and other incentives. I'm fine with policy that requires these things in public and even commercial buildings, but private residential is another story. Yu can certify aspects of these optional things that potentially increase the assessed value and incentives can be used to offset costs, but forcing you to do such things is an infringement on you freedoms. And the value of such things has a lot to do with the climate you are in. That gas a lot to do with how long it takes to payback on the energy,

Not only that, it puts immediate stress on supply chains. As soon as a policy is passed for more insulation for example, there is increased demand that the market takes time to normalize. This causes prices to increase in the short term, and supplier profits to increase in short term, causing windfall $$ to a few lucky people. Its is a tricky situation encompassing the environment, socioeconomics, and basic economics. @@professorg8383

@@garage3022 $50k, assuming 50% energy savings, is maybe 112 years until payback in our 15 y.o. Vermont house.

ok because NO CODE was ever "enforced" to turn a buck...

Coming from an engineer involved in construction for 20 years you have no clue at all. The "codes" are simply a money grab and a place for people to play cop.

Make everything too expensive, that way people can be safe sleeping on the streets.

85% of heat loss is thru roof. Cold floors do suck tho. Dont like how foam flexes under workers, hope fiber additive stops cracks in concrete.

I just poured my floors yesterday and my dirt was so uneven underneath and I had the exact question. We had to pour anyways but I worry about how that may affect settling in the future. We did end up using rebar 24oc hoping that helps hold it all together well.

Me too. I always expect code enforcement to make things more difficult, and expensive. You should know what the code in the area you are building on calls for. So should anyone that is pouring foundation, but ultimately it's the builder and homeowner's responsibility.

They are already pouring soup. What’s a little more water at that point??

They used fiber but I would only use steel