Rafter Framing 2

Renata and Matt are coming into town to help us frame rafters. They are both eager helpers! To prepare, Daniel and I hauled a super heavy, 36’ long beam up the flight of steps. From there the beam was raised another 13+ feet, until it came to rest on top of two end posts. This is dangerous work, so we proceed with caution. We erect scaffolding and bolt a series of 2×6 ledgers on the end walls. Then carefully, ever so carefully, we raise the beam from one ledger onto the next, and secure it within the end walls. We heave sighs of relief, congratulate ourselves with five-highs, and open bottles of….well, never mind!

The next task is to cut and install 24’ long, 12” deep manufactured rafters. This process requires considerable prep work. At the peak of the roof, the rafters are laid on top of the beefy ridge beam. At the bottom, they are attached to a 2×4 sole plate. Manufactured rafters can carry snow and wind loads over much larger spans than conventional lumber. Manufactured rafters allow us to create an open floor plan. On the down side, they cost much more than conventional wood rafters. Labor is costly too.

When designing the roof of a habitable attic one needs to be careful not to undersize rafters and beams. Insulation and venting cavities occupy each rafter bay. Earlier we had calculated the various design loads; a task most builders leave to the architect. Then we submitted our design for approval by the manufacturer. We were happy to learn that only a few minor changes were suggested. It bears mentioning that manufacturer’s installation instructions must be strictly observed else the product warranty is voided. Renata, my precious daughter, has taken excellent photos that show the many installation details. We brace the rafters; ever mindful of the damage high winds can cause.

You may be wondering how we keep the first floor dry over a period of weeks. Let me be frank: it is an ongoing challenge. The weather has been wild this year! We’ve have had several severe rain storms. Fortunately, the sheathing we use for the subfloor is treated to withstand water. Nevertheless, plenty of water leaks through the joints. I reason that a coat of tile mortar will seal these gaps. It does, but not as thoroughly as I had hoped. So…reluctantly… I purchased several rolls of synthetic roof membrane, tack them on the attic floor, and tape the seams. This water proofing method works fairly well.

By now the main roof is fully sheathed and covered with a roof membrane. The house is water tight! It’s time to play a round of bags!

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