What is going on???

wdecker · February 17, 2008, 12:49am

Radient heating (from the floor) does not heat the air that much. If there was some sort of air circulation (fan) in the garage, that would help.

Just because the garage is “heated” does not mean that the garage ceiling / bedroom floor should not be insulated.

Hope this helps;

jhagarty · February 17, 2008, 1:39am

I installed hot water radiant floors when I added onto my home. Temperatures are warmer at the floor and decrease as you reach the ceiling unlike a convection baseboard or radiator.

It is normal to see lower temperatures at the ceiling with an in-floor radiant system.

wdecker · February 17, 2008, 3:46am

Brian A. MacNeish:

It appears that this room would have kneewalls running from front to back and floor joists running side to side. If that is the case, the floor system may be prone to air leakage over/through the fiberglass batts installed in the floor at the point where joists support the kneewall …very common for this to be missed by a contractor with no experience with better energy conservation techniques. If the room is not heating properly on windy days, it’s definitely an air leakage problem.

(Note: I find that 95% of GC’s don’t have the knowledge or care about these better techniques as they are not covered by codes. Same with architects…if you don’t find someone, GC or architect, who is passionate about this topic and has association with R2000 / National Energy Conservation Association (NECA) in Canada or Energy Efficient Building Association (EEBA) / Building America or similar in the US, you will not get the building you should…we’ve known about these issues and techniques since the 1980’s!!!)

Agree! See it all the time.

lolsen · February 17, 2008, 6:28am

Another question

If there is air hitting the floor in the room how do we stop that? This is a totally finished house.

Thanks
Lawrence

dvalley · February 17, 2008, 12:48pm

Laurence,

A cheap way out of this, is to light an incense stick in the room in question. Then whatever direction the smoke is blowing, your infiltration is coming in behind it. Then concentrate your IR scan in that area. The slightest of cold air infiltration is not that hard to locate with my B-2.

Have you taken Level 1 Certification yet?

Brian_A.MacNeish · February 17, 2008, 1:25pm

“Here is a picture of the inside of the garage.”

http://www.nachi.org/forum/attachment.php?attachmentid=18661&thumb=1&d=1203146329

When I earlier looked at this pic, I thought that the floor had no insulation as the ceiling drywall was warmer than the bottom of the floor joists. If there is no insulation, the heat will also radiate downward and the ceiling becomes a heater (well, partial heater} for the garage below. If the radiant floor system was designed correctly, or even a bit oversized, for the room above, it will not heat the room on the worst days as a signifcant portion of the heat is moving downward by radiation. With a fully open floor cavity, air infiltration/exfiltration may have no resistance at all if the air barrier system was not the main concern of the GC.

The solution would be to blow the floor cavities with insulation. My usual choice is blown cellulose (due to its recycled content and it does a better job of restricting air infiltration than other loose blown insulations). In this case, with the floor joists on 24" centers, not 16", and not knowing the joist depth (hence total weight of materials that would be installed), I would use a lighter weight blown fiberglass so as not to have too much weight on the drywall and potentially cause other problems later.

Before blowing the cavities, you would have to check for water pipes if there is a wash/bathroom, etc in the bonus room over the garage.](“http://www.nachi.org/forum/attachment.php?attachmentid=18661&thumb=1&d=1203146329”)

dandersen · February 17, 2008, 3:42pm

You need to be looking at the HVAC system more and not necessarily the building envelope.

Insulation does not “make heat”.
It can not keep the heat in, that is not there.

Concerning the insulation capacity of the flooring system, this can be done with calculations obtained through infrared scans. This is taught at the building science course at ITC.

The room over the garage (here we call at the bonus room) has the highest heating and cooling load of all the rooms in the house simplyalmost all of the square footage of the ceilings, walls and floor or against a non-conditioned space. This room, because of its location is often difficult to get sufficient air flow to. Insufficient air equals insufficient BTUs.

These rooms are often large with cathedral ceilings containing large volumes of air. They often do not have a return air duct which is necessary to condition large volume rooms. If you don’t take the air out to be conditioned you substantially reduce the capacity to heat the room. Trying to mix hot and cold air is also inefficient due to air stratification in the properties of air. Hot and cold air mix about as well as water and oil. Adequate mixing of the year requires sufficient the lost city which is the bonus room frequently cannot produce.

I’m assuming you have forced air heating/cooling.

lolsen · February 17, 2008, 7:13pm

This is great guys.

David V.
I have taken the Level 1 and building investigations course through ITC in Canada.

I will look more at the HVAC unit when I go back when it is colder. I will try to take everything into consideration at that time. This will likely be late next week.

If there is more ideas let me know.

Thanks
Lawrence