Home Attic - Sealed or Vented?

I would expect it to get real hot in the attic during the summer without venting. The heat could shorten roof life, too. Then, during the winter, condensation could be a problem if moisture enters from the living space.

If you want insulation, put it in.

Generally, the closer you can get the roof space to ambient, the less problems you will have.

No experience with asphalt tiles. We don't use them here. They melt in summer.

I have houses in Arkansas, Arizona and Minnesota. They all have vented attics.

From one central Texan to another-vent and insulate. The stable climate inside your home Vs the roller coaster ride we call weather down here will create stagnant air, condensation, and even mold in a sealed environment. Also, a nice 4-12 will make for a good attic space that you'll want to ventilate.

vent it - air is a good insulator, but 200 degree air will bake your ceiling. My house (Houston) has vents under the eaves and one along the very top of the roof. For insulation - use insulation.

I'm no expert, but I'm pretty sure that a slab on the ground insulates better than any pier and beam - plus your pipes won't freeze.

My house that I have in Houston (I wasn't able to sell it, yet) has features that I don't like:

A 4:12 pitch roof. Practically, there is no attic, but a crawl area.

The pipes are run through the "attic". When the pores in one pipe became large enough, I had water pouring through the ceiling. To replace the porous pipe section, I had to do the job from the room, not enough room in the attic.

There are two vents built initially, on the roof top. Because the roof ended abruptly at the wall, there were no air intakes. I made it myself, on the North side of the house, in the porch ceiling. The best is to have the roof extend 18 inch beyond the wall, so you can have air intake. The roof should have the gap, on top (any builder will tell you about it), so you can have air circulation. Moisture will not accumulate, this way.

I would use a 10:12 pitch for the attic. You will have a nice attic, functional.

Use as much attic insulation you can afford. An equivalent R24 is minimum, I think. Use it on the attic floor.

The slab for foundation is, for me, the best. Pull all your piping through cement.

Asphalt shingles are good, they last 20 - 30 years, depending of price :-). During July, the temperature under the asphalt shingles is in the range of 140-160 degrees F. This is important to have a good ventilation immediately under the roof, and a good isolation between attic and the house. In Houston, the heating bill for winter is lower than the cooling one, for summer time.

With a10/12 pitch you may as well have a second story.

For sure. But, it won't hold any snow.

The rail road slope is maximum 7%. I understand now, why!

Properly sized,.... t-stat controlled,...... attic ventilation fans feed by gable or soffit vents......

• Not too much
• Not too little

No ridge vents or turbines.

In Central Texas we worry more about cooling than heating. If you don't vent the attic the air heats up and is trapped inside the attic thus it will start to heat the ceiling through osmosis. So vent it as much as possible, I recommend a ridge vent as close to 100% as I could get it. We generally put a high pitch on the roof (10:12 ) to reduce the direct angle of the sun. This prevents the shingles from deterioration.

The cost of putting in a pier and beam foundation is usually cost prohibitive. Most municipalities only allow a post tension slab. Recommended because of the soil conditions in Texas. We sit on an old ocean floor bed.

Good luck.

The slab can help offset the daily thermal cycles in Texas. Suggest you use insulation around the perimeter of the slab to a depth of 2 or 3 feet, and insulate the exterior surface of the slab. I live in College Station TX and my slab was not insulated this way, so it is cold in winter and hot in summer (I do have exposed sides on my slab). There are contractors here who will seal existing attics with urethane foam. They claim 50% reduction in energy savings. Seems they have been doing it for ~ 3 years, so its too early to tell if it will damage the roof. In new construction I would use insulating panels for the roof deck. HAVE FUN

Suggest you use insulation around the perimeter of the slab to a depth of 2 or 3 feet, and insulate the exterior surface of the slab.

Food for thought. Take advantage of geothermal heat sourcing and sinking.

My house in Tallahassee (similar climate) had a 6/12 pitch roof. That's as steep as you can walk on without safety lines. We insulated the floor of the attic area and ran a vent along the roof peak.

I recommend a metal roof if affordable in your area.At least a 5/12 pitch.Full ridge vent, and fully perforated soffit boxing.You can even get a tax credit for certain colors, due to the energy efficiency.

The metal roofing has a ceramic coating that reflects heat,and it will last at least 50 years.

If you cannot afford metal, go with fiberglass shingles.Most last 40 years or more.Roofers don't like them, because they are so hard to cut.They have to keep changing their blades.

Vented, unless you plan to dry meat up there. The best installation I have seen is insulation batts right under the roof, plus blown-in insulation with flooring over it, and turbine vents on the roof with plenty of soffitt vents. In the middle of a Texas summer, this attic was only slightly warmer than outdoors.

Vent the hell out of the attic, put in continuous ridge vents along the peak and make sure you have LOTS of vents under the eaves continuous if possible. NEVER EVER seal an attic! Especially not here in Texas! you'll superheat the air in the attic and that heat will make it's way into the house. A sealed attic will be at least 30-50 degrees(F) hotter than an unsealed and properly vented one will. Use foil backed decking ( Louisiana Pacific calls their product Techshield, not sure if there are other suppliers.) with the foil facing the living space. this will act as a radiant barrier and reflect the IR heating back to the outside keeping the attic space even cooler. by doing this you can keep the amount of insulation needed on the ceiling to a reasonable R30. Put R11 in the walls and under the floor (if pier and beam) and then staple a vapor barrier across the beams to prevent moisture from the ground from soaking the insulation. Wet insulation is not an insulator at all and it grows mold like nobody's business. I'm not a big fan of pier and beam myself, but it has it's following. DON'T make the mistake of trying to use a pretensioned slab foundation. They are entirely too flexible and it will fail on you eventually. All the tract house builders use them because they are cheap to build/pour, but your best bet is to build a conventional reinforced concrete foundation IMHO.

BTW, don't use OSB type decking for the roof, it is cheap and every builder uses it for that reason, but over time it will swell and warp and pop loose at the joints causing the shingles to fail. use conventional marine/roofing grade plywood. You'll be glad you did. I'm not sure if techshield is still available in a plywood product, they may be OSB only (builder demand don't you know.) now. Seems like I remember that they had phased out the plywood version. I'd investigate this. if it comes down to using an uncoated plywood vs coated OSB, go with the coated OSB. the savings in HVAC costs will definitely offset the shorter shingle life.

Now I'm about to tell you something that will really make your head spin. when installing your HVAC system, put in a small (say 4-6") FILTERED outside air intake ducted from one of your eave vents into your return plenum. This will have the effect of pressurizing your home above the outside air pressure which will prevent dust and pollen being sucked into all the myriad little cracks that every home has. the easiest way to do that is to put in a large pleated bag type (4-6" deep) filter at the air handler and letting all the unfiltered return vents go into a common plenum that feeds the filter, you'll only have to change the filter once every 6 months or so. the loss in efficiency will be miniscule, and the advantage will be better indoor air quality because you won't be constantly recirculating indoor pollutants like formaldehyde that outgasses from carpets and plywood and particleboard and insulation. Also don't go for the very high efficiency units here in Texas. They do not remove enough moisture from the air and you end up with moisture problems every time. A SEER of 13-14 is about as high as you can reasonably go in our climate without problems. The higher efficiency units are fine up north where the cooling cycles are shorter and the humidity is lower.

Trust me, I've lived in Texas my whole life and this ain't my first rodeo.