Heat loss through concrete wall

JD_7

I like this idea i may just try it. Thanks!

JD_7

Heat Loss Through Concrete Wall

I have a 600 sqft rec room built around the turn of the century. They used poured concrete (strange I know)for the walls. The room is heated with hot water baseboard installed in 1919. I have replaced all the windows in the room added insulation to the ceiling but the room is still too cold to use when the weather is under 40. Will adding new baseboard like runtal make any difference in heat output into the room? Also any suggestions on insulating a room built of solid concrete?

Brad White_9

BTU's are BTU

> I have a 600 sqft rec room built around the turn

> of the century. They used poured concrete

> (strange I know)for the walls. The room is

> heated with hot water baseboard installed in

> 1919. I have replaced all the windows in the

> room added insulation to the ceiling but the room

> is still too cold to use when the weather is

> under 40. Will adding new baseboard like runtal

> make any difference in heat output into the room?

> Also any suggestions on insulating a room built

> of solid concrete?

Brad White_9

BTU's are BTU's

Either radiation form will work fine if properly sized. Runtal can tolerate cooler water temperatures and have a higher radiant output than fin-tube (depending on the model of Runtal you choose, of course). Higher radiant output will allow some leeway in percieved comfort at lower room temperatures.

What you did with the windows and ceilings is good, but concrete is a heat sucker. Slow to heat, slow to cool but darned conductive. It has an R value of 0.08 per inch, kind of useless.

So what you did was put on socks and forget the rest of your clothing..

When teaching, to drive this home I ask how many inches of concrete will it take to equal the R-value of an inch of extruded polystyrene? (Being R-5 by the way). Answer? 62.5 inches of concrete. That is a thick wall. My point being in all of this, can you insulate the walls? And preferably on the exterior?

Here is how I insuated my concrete walls:

I bolt 2x4's as ledgers horizontally across the top and bottom along the wall using Red Head bolts and a masonry hammer drill. 3/8" is fine and use a carbide tipped bit.

Between the 2x4's I lay in 1.5" polyisocyanurate board (R11 roughly). Then over this I screw 3/4" plywood and paint it. You can hang stuff on it (like my boiler and lots of piping) or finish to your choice.

If you want to thicken the insulation a bit consider nailing a sole plate to the bottom ledger and put in batts or another layer of foam board staggered to the first. Cover with ply or GWB to finish. If you can get an airspace in front of any foil faced insulation you can pick up an R value or three.

Mike T., Swampeast MO

Probably the best way to insulate such is from the outside. Think EIFS (exterior insulation and finish system) like Dryvitt. Once you have the mass of the walls up to temp you'll get very good comfort as long as you don't use very deep, daily setback. If A/C is used in your area it will also help GREATLY to reduce your cooling load.

The alternative is insulating the interior. Rigid insulation offers much more "bang for the inch" than other forms. Of course this requires completely new interior walls.

Xc8p2dC_2

Been researching

this for my Unfinished concrete basment. On a concrete/masonary/ brick wall you can only have a vapor barrier on one side. The poly/styro/xps/eps type products work very well on the outside of the foundation [but you have to make sure something [insul or sealer] is not on the interior wall

If your foundation is below grade and backfilled, it is important to know if has been sealed [tar type product]
If so, you can use poly/stro/eps/xps type products directly against the interior wall [btw in most states any studs that touch cement etc have to be pressure treated ]

The problem with poly/stryo is it is NOT Fire proof, so to remain in code you have to use Gypsum/sheetrock over it

If you can stud the wall and not put the stud againt the foundation, you can use normal fiberglass batting [NON KRAFT FACED] but you must not have the batting touch the concrete wall and use a netting to create an air gap between insul and concrete

There is a newer type of insulation that is made from recycled cotton and is class A rated for fire and also mold/mildew proof and may open some options for you

Hope this helps

Brad White_34

I agree, Mike

Insulating outside the mass is the best by far. I went on a rant about insulating the interior thinking (not knowing) what the outside grade was. Never seen anyone excavate just to insulate. Agreed the EIFS/Dryvit systems are good. We *did* notice a problem on one job I did: Morgan Library at Colorado State in Fort Collins. The architect specified cementitious stucco to 8 feet above grade and EIFS above that including screen walls for AHU equipment. Turns out woodpeckers just LOVE the stuff as a nesting material and within it too. Cozy and energy efficient! Given a choice: Cement plaster on metal lath above grade. Still, a good call.

Brad

Doug_7

Wallmate Slotted Insulation

One quick way to insulate a concrete basement wall to R-15 or R-20 is using Wallmate slotted extruded polystyrene insulation. It is an interior wall system made for this application that avoids framing.

Works best if the wall is straight.

See: http://www.dow.com/styrofoam/na/res-us/products/wallmate_slotted.htm

Cover with gypsum board for fire code.

Doug

Plumbob

I have this problem in the basement, a lot of heat is being lost there. My question is, is there a simple solution when previous owners have over time placed plumbing and electrical conduits along the walls? (Will it help to cover say 60% of the wall area, which has no pipes or conduit on it?)

Also, what happens if there is a water leak in the concrete wall? This has happened before, it's a 90-year-old house.

Brad White_35

It will help to insulate

whatever you can, but not in a way that I think you will "feel". My basement is that way and I did not take "Before and After" readings. I am sure the heat loss is less but the remaining unisulated walls do suck the heat out of you still. I did what I could.

If you have a water leak, you just have to fix it. Hydraulic cement is the way to go. It expands when it sets for a tight seal. The ILG line of products (interior applied epoxies) always look good in the lumber yard displays, but I have an issue believing that external hydrostatic pressure will not push it off the wall at some point. External solutions work best -including insulation solutions if you can! If you cannot fix the leak, almost no point in trying to insulate it.

Xc8p2dC_2

drainage

If you have visable water leaks in the wall, you will have to install a drainage system inside along the floor

Usually requires digging a 12"+/-, wide culvert along the lenght of the wall and filling in with stone

The product in the link above, is the eps/exp type styro boards that works very well, what you do is put a 2x4 header and footer at the top and bottom, but use a 2x3 as the stud to hold the poly againts the wall and attach sheetrock to [if not touching the foundation they don't have to be PT]

JD_7

Thanks for all your help guys, I should have added my caveots
The concrete was form poured, but above grade, then stuccoed 4 ft above grade. The first 4ft was left unfinished
here is a picture
http://hornbacherhouse.blogspot.com/2005/08/house-history.html

Does the stucco offer any r value? Will insulating just the bottom portion of the exterior then finishing in cedar siding help?

Mike T., Swampeast MO

Stucco has essentially the same (very low) insulation value of poured concrete as it's nearly identical in composition.

Is the room in question the one with two separate but closely spaced windows on the two sides I can see in the photos?

If so, an EIFS system would work and could closely match the appearance of the rest of the house, but you'd really need to remove and re-install (possibly replace) the windows. I was imagining windows inset into the concrete wall--such would have made EIFS easier.

To be effective you need to insulate all of the wall surface--either from the outside or the inside. If you only insulate a portion the high conduction of concrete will render the insulation almost useless.

JD_7

Yes that is the room in question. Unfortunately i replaced the windows last season (not shown) so it looks like I would have to have them removed and reinstalled.

Weezbo

here is a way to gain some chance of insulation ...

though losing some of the thermal mass.

sound insulation between rooms in partitions works well also.

outside applications of water proofing is the best practise. wicking and the like, are definite areas of consideration often overlooked.

for many years we have used out door applications of insulation water proofing and sealing .

As Mike said outdoor applications with a finished Drive it is a very sharp way to cruise.

While you can get some very sharp cosmetic changes indoors by applying sealers furring strips or metal studs or false walls and insulating. installing vapor barrier, sheetrock mud tape and texture prime and painted you lose the thermal mass of the poured wall and there is likely to be some minor technicalities arise down the road... alot depends on humidity and pressure control( controled ventilation) within the building envelope.

here is a picture of where internal application of insulation might work ,like i say depending on controlled ventilation and humidity.

Mike T., Swampeast MO

Think you might have missed that this was an above-grade room with concrete walls--not a basement.

Xc8p2dC_2

Neet house

I would assume from the Pic the floor is ground level?

If so, when you insulated it did you use a plastic barrier that came down from the ceiling over the wood part of the wall then down the foundation?

The foundation will have to breathe from only one side>> you may be a good canidate for the Styro type panel products glued to the outside, then you would screw thru the sheeting into the foundation with plywood and add the wall covering of your choice[shingles. clapboards or you could even keep the same paint sceem

what you will have to know is, if the outer foundation wall was ever sealed/ tar or similar

or your original thought, bigger emitters

Xc8p2dC_2

afterthought

Run to your local bigbox [HomeD or Lowes]pick up some 4x8 sheets of 2"xps or eps and prop them up against the outer wall>> usually run $15-$20 a sheet

Then you will see if there is any big benifit>> If you don't cut or damage the panels, you can probably return them if no benifit

If there is a benifit, you could glue the sheets to plywood paint them, then temporarily lag them to the foundation then remove for the non heating season