We’re sheetrocked, taped, primed, and trimmed most everywhere. The painter is puttying, filling, caulking, repriming, and getting ready everything on the top floor in prep for spraying late this week.
The snow buildup on the roof is about 20 inches, and today, the second day after the snowstorm of bright sunshine, high temp maybe 22, I notice I have monstrous icicles all along the eaves, with big ice dam buildup on the edges. No other houses nearby with ice, at least none with what I have. What did I do wrong, I thought. We air chuted, ridge vented, sealed up every critical area with sprayfoam urethane, and the topfloor ceilings have at least 16 inches of cellulose above them.
Then it dawned on me. Every upstairs room has at least two ceiling penetrations, still not finished. Fan boxes, light boxes, smoke detectors, vents, holes everywhere.
The finish trim for all these will seal off much of the heat that is escaping now into my attic and melting the snow on the roof, but what additional precautions should I be taking?
I have one canlight only, and it is an IC box, for which I ordered the Juno air-loc gasket like I always do.
But all those other things. Canopies for the fans, the smoke detector flanges, etc. Should all those be caulked?
Replies
This is a good illustration of several of the discussions on BT lately - particularly remarks by CSnow - about the importance of stopping air leaks into the attic. I'll be watching the melting patterns on my roof to see where I should be looking for more chinks in the armor.
I think unilsulated recessed lights may be one of the great causes of ice dams. Many people insulated after the energy crisis of the 70's, but added stylish recessed cans in the go-go 80's. We haven't had real ice dam conditions around here in years (This storm is close!), but when we do, there's going to be many ruined ceilings.
The other very risky trend is the siting of hot-air-heat air handlers in the attic. When conditions are right, this source of heat right under the roof is a guaranteed problem.
Al Mollitor, Sharon MA
I have two Aker acrylic bath units on the top floor, one a tub/shower, and the other a shower. Each has a can-light in the integral ceiling. For both, I built a sealed box above, the size of the whole bath unit, with the tops clearing the light fixture by at least 8 inches. The blown-in cellulose sits on top, at a thickness of 16 inches. Those cans are OK.
I think I will have my electrician bed each light fixture canopy and each smoke detector in a small perimeter bead of latex caulk, when we finish up.
Most of the builders here strongly discourage ceiling lights in the uppermost floors, for that very reason. Ceiling boxes are sealed with vapour barrier etc etc, to prevent air leakage.
You are right about air handlers sitting in the attic full of hot air.
On a frosty roof, you can find the air handler from the street.
I advise sealing all seams with aluminum tape, easy to cut with razor blade knife to get into unit. I then make foil backed foam board panels to fit each side, and al tape them on to the AH.
Also Micro should look at the hvac boots for air leaks, and weather strip/insulate/double door or lid whatever the access is to the attic.
PaulEnergy Consultant and author of Practical Energy Cost Reduction for the Home
You still using temp heaters to heat the place? (propane - torpedos) Windows open for ventilation?
This is a good time to search for air leaks.
Wait for a cold still day (or night).
Open the front door, then go upstairs and look for evidence of leaks.
There are a number of methods for detecting leaks.
Some pros use smoke pencils, but you can use;
1) A smoldering match, wooden stick, or piece of paper (obviously, use caution)
2) A cigarette
3) Spray bottle that makes a fine mist.
4) A piece of toilet paper
Watch where the smoke/mist goes, or the TP flaps about.
Amazing what you can discover with this low-tech sleuthing...
Best of luck.
Where do you use smoke, etc. to test for leaks? In the attic, or the top floor?
Al Mollitor, Sharon MA
Top floor. Positive pressure vectors up there.