My Current Huge Project With Radiant In Floor Heating

In the old place, the big redbrick fireplace was a huge heat sink to the outdoors, the walls of the family/TV room had only 1" of fiberglass insulation, very poorly installed, I did install new windows, and insulate the ceiling to more than R30, but the heat would come on about every 30 minutes. Even in 30* weather, the place bled heat.

Now, the hot water heated concrete slab only seems to call for heat about every 3-4 hours, I've only noticed it heating twice in the last 10 days, now of course I'm not there monitoring the temp guages all the time, but everytime I walk by the water distribution manifolds, I look to see if the supply side is hot or not.. so far it seems like 99% of the time, it is just circulating 65* water, and needs addtional hot water to keep at that temp only a few times a day, and only for about 5-10 minutes at a time. The slab just stays warm..

I can't wait to get the ceilings in, and insulated.

My current task at the top of the list is to wire the kitchen, the cabinets are in, and stored, the appliances are in, and stored, I really need to get the kitchen together to so I can get the cabinets installed, the granite countertop templates measured and made.

Looks real good! You're gonna love that radiant floor heating

The insulation plan is to use 2" of spray foam, then fill the remaining space in the 2x6 walls with r13 fiberglass insulation. You're right, the closed-cell foam is R7 per inch. I'm spraying the foam myself, using kits available on the internet. The foam is expensive, but every dollar spent on insulation is returned tenfold within a few years. So I'm going all out with sealing and insulating.

The entire house has full eave soffit vents, and full ridge vents.. my attic temps stay quite reasonable.. I removed and rebuilt the roof structure on the old part of house about 10 years ago.

The ceiling insulation will be at least 1" of foam sprayed on the top of the ceiling drywall [sheetrock]. [probably more] The foam will be covered with fiberglass bats. Many foam insulators spray the underside of the roof, to eliminate the radiated heat from the shingles entering the attic. I may do this on one section of the attic, and monitor the temps in the summer.

The spray foam kits are really neat, I can tackle a room or a section of the house, as needed. The professional foam insulators don't do small sections, they want to spray a whole house at a time.. With the kits, I insulate as I need and am ready. The floor joist spaces over the sills will be sealed and insulated with foam, eliminating a major area of heat loss in most houses. My concrete basement walls have R14 foam board insulation on the outside, and I may eventually stud-out and insulate the inside of the basement, but so far the walls are staying comfortable at 55*, the ceiling above [under the heated 'suspended slab'] is about 58*, so the basement is comfortable. Even with no hot water circulating in the basement floor yet.

Greg L

Wow very impressive work. If you don't mind me asking, how much does all of this project cost?

Greg, while the walls are open, don't forget to use the blue fireproof expanding foam on all the electrical/plumbing pass-thrus. That'll also keep bugs from getting into the house via the wall switch and outlet boxes

I got some quotes on it last year - I was going to go with 4" on ceiling (which is directly on roof sheathing) & 3" on the walls, which is pretty much all I could do up there with the space I had. They wanted $6,000 just for the upstairs (ceiling & walls).

But it's the only way to go for the warmth factor. Plus it sound deadens, adds structural stability, acts as a vapor barrier, & stops all air infiltration. It was the solution to every single problem I have in this house! I priced those online kits & it was cheaper to have someone do it for me, after I factored in the amount of kits I'd need & the shipping.

I might have to take another look at this though - maybe only do an inch or 2, rather than go all out. This year we abandoned the entire second floor & moved our bed downstairs. I have 2 pieces of 3/4" plywood that are hinged to the wall, & will fold down & completely seal off the stairway to keep all the warm air downstairs where it belongs.

SMITTY wrote: I have 2 pieces of 3/4" plywood that are hinged to the wall, & will fold down & completely seal off the stairway to keep all the warm air downstairs where it belongs.

Smitty, buy a piece of rigid 2" x 4' x 8' insulation from H.D. or lowes. Use some 3" bugal-head screws to screw it to the face of your 3/4" 'door' to save you even more BTUs

Good idea! Thanks!

Looks good Greg, get it done and get back to work here.

Richard's got the whip out again! :whip:

The spray foam is used to seal all the outside walls, wire and pipe passageways. One of the huge advantages that closed cell foam has is that it is based on glue, it is an over-catalyized glue.. when it is sprayed on a surface, it sticks. as long as the surface is clean and not wet or covered with frost. an 1/8"-1/4" expands to 1"+. With each stud space sealed from outside air infiltration, the house is TIGHT. No air infiltration equals no cold outside air mixing and cooling the heated inside air.
Fiberglass is a good insulator, but a lousy sealant. in a sealed space, fiberglass works well. In a space with lots of air movement fiberglass just doesn't work well at all, so the combination of a foam sealed space and fiberglass is quite effective.

Greg L

That's exactly the problem in my house - major air infiltration. That, and there isn't enough fiberglass to begin with because there's no room - it's right up against the roof sheathing on the 2nd floor - a big no no. So if I were to do it correctly by installing foam channels, now the fiberglass will be compressed & rendered useless. Foam is the only solution.

This is great - I've been waiting a long time to get some info on the stuff from someone who is actually using it! I'll be watching for your updates - I'm sure your fuel usage is going to plummet by a MASSIVE figure! :nice:

I sure hope so, it [coal use] does seem like it is a lot less right now, but I'll have to have a few months of real winter to tell. Do a google search for 'spray foam insulation'. The stuff I bought is from Chicago Ill. The cost is about $1 per square foot an inch thick [one board foot]. But one inch of sealed R7 is more effective than any amount of fiberglass in an unsealed, convective space. When you google the spray foam insulation, look at all the videos and studies.. they are very interesting.

Greg L

LsFarm wrote:I sure hope so, it [coal use] does seem like it is a lot less right now, but I'll have to have a few months of real winter to tell. Do a google search for 'spray foam insulation'. The stuff I bought is from Chicago Ill. The cost is about $1 per square foot an inch thick [one board foot]. But one inch of sealed R7 is more effective than any amount of fiberglass in an unsealed, convective space. When you google the spray foam insulation, look at all the videos and studies.. they are very interesting.

Greg L

I've used a lot of that stuff in our house. Where it becomes HUGELY valuable is when a house is sheathed in boards instead of with plywood. Under the siding our exterior sheathing is 1 inch thick boards of various widths and lengths. There are gaps between each one. The wind just blows right through that. Whenever we open up a wall we spray foam as much as we can. It makes a huge difference.

BTW. Great project. Nice work. How much are you doing yourself and how much are you subbing out?

That's exactly the problem in my house - major air infiltration.

Same here, I'm very interested in the spray foam. The kitchen addition is well insulated but the main house only has fiberglass in the attic above the second floor and only in walls that I have had open. This place is a giant air leak. The porblem with using fiberglass here is the house is post and beam construction, no 16" or 24" studs to attach the fiberglass to.