Another unsexy thing I recently embraced was some salvage operations in my garage. If you know old properties, you’re probably familiar with the circa 1950’s garage. Detached, built sometime after the house and not to last, long before the modern almost-as-structurally-stable as the house outbuilding. The door isn’t tall enough for a large pickup truck. The concrete floor has no rebar. It isn’t insulated, wired or weather tight. It might be on your neighbour’s property and inhabited by critters. Mine has a clan of chipmunks and many spiders.
I don’t know anyone who parks their car in such a garage, but if you have one, you probably use it for storage and don’t want to take it down because of the value of existing structures within municipal bylaws. Thus, my goal with this dilapidated garage is to keep it from falling over, because it would be embarrassing, inconvenient and expensive if it did.
The initial stage of my expedition to make the garage sound was to identify rotting or compromised wood (that is what the structure is made of, with vinyl siding and asphalt shingle roofing). Startlingly, the rafters are on 36″ centres, there’s some odd remedial work on the roof joists and wall studs, and a few areas of wood rot or damage.
Non-structural rotted wood I sprayed for bugs, then soaked in liquid epoxy, which absorbs into pithy wood and dries to a solid. I’m primarily concerned with keeping bugs (carpenter ants, termites) from devouring weak wood, so hardening should do the trick.
Despite the 8 ft. span of the rafters, the collar ties are about a foot from the peak, which puts quite a stress on them. Two pulled out of their fastenings. These I supplemented with a collar tie 4 ft in length (yes, conveniently half a standard 2×4). Like cross bridging, the tricky part was the angle to match the rafter. To make a long story short, I ended up tracing the angle from the existing (not attached) collar ties on a piece of paper and it worked perfectly as a guide to cut the new support.
Otherwise, the only rotted wood that really concerned me was the sill plate at one front corner. It was mush, and had the original job of holding up the garage door and the front corner of the building. There was a bizarre collection of wall studs in this corner. One, with true dimensions (real 2×6) had a footing, amid the current 2×4’s on either side.
Before I started digging out structural supports, I cross-braced the vertical members. The ‘column’ was rotted at the connection to the concrete, so I used pressure-treated lumber to sister it on both sides, resting the sisters on the intact poured concrete floor.1 Then, I replaced the sill plate, slipping an intact piece of ‘brown wood’2 into the place vacated by rotted wood. And threw in some brackets to keep the various wood components connected.
Why hasn’t the corner of the garage collapsed because the sill plate was rotten? Theory says that a rotted piece of the structure should lead to settling but studs that should be resting on this rotted member are happily suspended in mid air. Nails, I’ve heard is the explanation to structural components not falling down when they aren’t supported from below.
I felt a lot better when I knew there was an intact piece of lumber supporting what needed supporting. Still not very sexy DIY, even with new bits of wood. But I know in my heart they were the right things to embrace.
1 Yes, this means the floor was poured below the level of the footing. IDK. I put stable on stable.
2 Some day, I will understand all the terminology for wood that’s had something done to it to make it more resistant to the outside = water, temperature fluctuation. For now, I’m using terms like ‘pressure treated’, ‘brown wood’ and others to indicate wood that’s sold as longer to last outside.