Sunday, April 25, 2010

Second Roof

Hi all,
Second roof took the best part of the week. The first roof and wall assembly gave us a continuous air seal and insulation cavity without the punctures that rafters produce in the envelope.

Three reasons for putting on a second roof framing and foam:
1- Second roof is added to achieve a higher overall R value,
2- It eliminates the roof's cavities from reaching dew point and condensation within the cavities,
3- It achieves our 2 foot over hangs.

We stayed home Tuesday waiting for a rain that never happened. Next week we begin exterior treatment and hopefully get our composition roof shingles finished.
See you next week.........Terry

The plywood and all the framing members were sprayed down with a 10% solution of boron. Damp and dry wood termites leave their nest colonies and fly off every year to recolonize. They hit a building at all levels in mass looking for holes and cracks to crawl into and start a new family in wood fiber and darkness. First defense for a structure is no holes or cracks in the assembly. Second defense is to soak down all the wood with a boron base application. Boron is not a neurotoxin, like most insecticides, and does not directly affect the nervous systems of termites and wood boring beetles or humans or pets. Boron is an enzyme inhibitor. When termites bore into the wood they are forced to eat the boron as well. Boron messes with all the body functions of the critters including their digestive system and they sadly wither away with a host of problems.

Termites prefer to start their inward journey through end grain so we double soaked the rafter tails with boron before the facia was applied.

Second roof applied over our first air seal roof. Now we have two foot rafter overhangs. This layer does not need to be air sealed. The 2x4 "sleepers" were attached with a nail gun from the underside of the plywood. They are set in between the 2x8 rafters below to minimize the thermal bridging between the two roof assemblies.

3 1/2" polyisocyanurate (rigid foam) set in between 2x4 sleepers.

Sleepers and foam ready for plywood.

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