attic in detached garage after spray foam

[bd8134]

Nice space james_b. You will have to check on what the requirements are for your heating zone. The rafters do not look very deep but you might be able to insulate with closed cell foam and Sheetrock on top, depends on what insulation value that will give you.
Done right your heating and cooling requirements should not be high. Our non-vented attics are about the same temp as the house, we have no need for additional living space, for us we wanted a better insulation value for the house.

 

[volleyball]

Yes, closed cell to fill the under roof, the rafters and maybe the chimney. Then you would have to go with better windows but that would be a great space to have. If you ever reroof, you could put it on top of the deck and under the roofing and leave those boards exposed.

The leaning chimney was not unexpected, it looks intentional. It is a common way to line up the roof and chimney

 

[bd8134]

I am not sure it will be code to spray on the chimney. They used Rockwool on mine to prevent the spray foam from touching the chimney.

 

[James_B]

Nice space james_b. You will have to check on what the requirements are for your heating zone. The rafters do not look very deep but you might be able to insulate with closed cell foam and Sheetrock on top, depends on what insulation value that will give you.
Done right your heating and cooling requirements should not be high. Our non-vented attics are about the same temp as the house, we have no need for additional living space, for us we wanted a better insulation value for the house.

It is a stunning space. The attic really was the decider when we were house shopping.

The family that built this place in the late 1800s/early 1900s (nobody knows for sure), were timber cutters and had 2 sawmills, so they cut lumber to suit what they were doing.

The majority of the rafters are a true 6"x2" so there's a full 6" depth to play with between the rafters. There's some smaller true 4"x2" rafters in a small bump at the back in the SW corner, and the 4 dormers have 3"x2" or 3"x2.5" rafters. The main beams at the roof line corners are a true 8"x2.75". Nothing in this house is undersized.

 

[James_B]

Yes, closed cell to fill the under roof, the rafters and maybe the chimney. Then you would have to go with better windows but that would be a great space to have. If you ever reroof, you could put it on top of the deck and under the roofing and leave those boards exposed.

The leaning chimney was not unexpected, it looks intentional. It is a common way to line up the roof and chimney

The chimney lean is intentional, but at the moment, we don't know if the brick work will be staying, or if the whole chimney will be replaced by the current style insulated chimney sections.

 

[goldenboy9r]

If you are only cooling below attic, then the attic space will be hot an humid in the summer. After all you are in Houston. On the bright side it will be cool and humid in the winter.
By insulating the attic ceiling your create a thermal barrier between you roof and ceiling which will lessen your thermal load on your interior space making it easier to cool. Your best bet would be to put a dehumidifier up in the attic.

If you have a ceiling below the foam and the area is sealed, it will be hotter or cooler but more humid.
a couple of vents in the ceiling to allow air to circulate will allow the moisture to equal the space below the ceiling

I am an HVAC tech , we love the spray foamed attics! Usually in the summer it is 120 degrees but with foam it is around 80. The foam basically seals your home completely off from outdoors , no attic ventilation , defeats purpose. Some homes are too tight and they do have a powered ventilator sucking in outside air into conditioned space but it heats or cools the air , basically another mini hvac unit. As far as your location , that is one of the most humid places in Texas! Lol! If you keep having moisture issues you may have to put a dehumidifier in your attic to remove it , watch for mold growth! As far as venting ceiling to garage area , just remember you will be adding extra heat load to HVAC equipment and it may not cool your garage then.

Putting vents in the ceiling to the attic would most likely make the situation worse.
Stale, moist, dirty air is not something you want trapped up there.

Interesting

So far my options seem to be:
1. Add a dehumidifier
2. Install vents in ceiling to allow air from conditioned space to attic.


I called the company who did the install and they suggested there is not enough "natural exchange" between the two spaces. Said vents on roof would defeat the purpose which was suggested here. Suggested installing vents on the ceiling but said he would call his regional manger to confirm first.

Still not sure how to solve the problem.

 

[bd8134]

Interesting

So far my options seem to be:
1. Add a dehumidifier
2. Install vents in ceiling to allow air from conditioned space to attic.


I called the company who did the install and they suggested there is not enough "natural exchange" between the two spaces. Said vents on roof would defeat the purpose which was suggested here. Suggested installing vents on the ceiling but said he would call his regional manger to confirm first.

Still not sure how to solve the problem.

1. Adding a dehumidifier into the attic, which could help the moisture content, will raise the temp in the attic. Then the issue of draining the water, leaks, cost of running etc.
2. Installing vents in the ceiling will allow the warmer air at the top of the ceiling into the attic, possibly the moisture also. To keep just more and more hot air from rising you might have to use power vents also blowing the hot moist air down.
You say you had 6" of open cell sprayed on the roof sheeting.
6" of oc at 3.6R value is 21.6 which would be pretty low by todays standards, I have seen 48 recommended for Houston.
How deep are your rafters?
Did they spray over your rafters?
Spraying over the rafters will give you a thermal break.
Did they spray or install any sort of fire barrier which I believe is required?
Increasing the amount of insulation to me sounds like a more long term solution.

 

[goldenboy9r]

they sprayed over the rafters