DIY Builds
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Can you put insulation directly against roof?

Experts usually advise builders that you can't install fiberglass insulation directly against the underside of roof sheathing.

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UPDATED on August 31, 2018 with new information on code changes allowing the use of vapor diffusion ports. Experts usually advise builders that you can’t install fiberglass insulation directly against the underside of roof sheathing. If you want to install fiberglass between your rafters, you have two basic choices: either include a ventilation channel between the top of the fiberglass insulation and the underside of the roof sheathing, or install enough rigid foam above the roof sheathing to keep the roof sheathing above the dew point during the winter. These rules were developed to prevent damp roof sheathing. Most building codes (including the International Residential Code) allow just one exception to these rules: in Climate Zones 2B and 3B, you can install fiberglass insulation against the underside of your roof sheathing without a ventilation channel or rigid foam above the sheathing — but only if you install tile roofing. (This system works because concrete tiles and clay tiles are well ventilated and vapor-permeable, so any moisture that accumulates in the roof sheathing can dry toward the exterior.) The code exception can be found in section R806.5, subsection 5.2, of the 2012 IRC. (Of course, if the owner of such a home decides to re-roof with asphalt shingles, the roof sheathing may begin to rot. But that’s another story.) Owens Corning, a leading manufacturer of fiberglass insulation, is now promoting a package of products — basically blown-in fiberglass insulation and a new type of insulation netting — to create unvented conditioned attics. Owens Corning calls this proprietary insulation method the “ProPink High Performance Conditioned Attic System.”

Surprisingly, Owens Corning is promoting this approach for unvented roof assemblies without any rigid foam above the roof sheathing. Does this make any sense?

This approach violates the code

Some Owens Corning documents include fine print warning builders that this…

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Should I caulk cracks in concrete?

Stopping water from flowing under your concrete is probably the most important thing you can do to keep your driveway from sinking and becoming out of level. Caulking the joints and cracks is the best way to stop this from happening. Even expansion joints in your concrete driveway should be caulked.

Why Caulk Concrete Cracks & Joints?

Water is the number one culprit when it comes to damage to your concrete and the foundation underneath. At A-1 Concrete Leveling, we know that even if we do everything right, and get your concrete looking like new again, but don’t take care of the underlying cause, it could all be for nothing in just a few short months or years. Concrete Driveway Crack Repair Stopping water from flowing under your concrete is probably the most important thing you can do to keep your driveway from sinking and becoming out of level. Caulking the joints and cracks is the best way to stop this from happening. BEFORE — Even expansion joints in your concrete driveway should be caulked. They can be the biggest culprit of water under your slabs. AFTER — Notice how the caulking is slightly lower than the concrete slab around it. This protects the caulk from wear and tear of people walking and driving over it. Water will do its best to find a way under your concrete and do its work of washing out the subsurface, or through freezing and thawing heaving the concrete and creating voids. This is why it’s critical to caulk the joints and cracks. Expansion joints are necessary to allow the concrete to shift around during changes in season, but those same joints are the perfect place for water to get under your slabs. ​​​​​​ Allowing A-1 to caulk the joints with a flexible, long-lasting caulk is one of the best things you can do to prevent future issues with your concrete driveways, sidewalks, steps, pool decks, and more.

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