The Roof Sag Conundrum
When we were called in to come up with a plan to deal with a sagging roof, we did not expect what we found. This stick built home with a cathedral ceiling above the main living space had a roof ridge deflection of approximately 10 inches. This deflection resulted in pushing out the sidewalls. It was obvious that this structure had been stressed to its max and it was only a matter of time before it failed.
While finding a solution we had to consider was the newly replaced metal roof. When this roof was replaced the top side of the roof was furred up to conceal the deflection. Ideally the deflection would have been dealt with, raised back into position and a beam placed prior to any roofing.
Now we had a dilemma, how do we fix this without damaging the brand new roof? We can't raise this back into position without buckling the roof but we have to provide support because it is doubtful that it would make it through another winter snow load.
We opted for the placement of a double LVL (laminated veneer lumber) beam. With the help of manufacturers software and our friendly local lumber supplier we specified a double 2x12 LVL to span the 20 ft distance. Unfortunately without jacking the roof back up we could only catch the load in the center of the span and shim from there. We bolted posts to the existing posts and ensured the loads were transferred to the foundation.
By catching the sagging load and shimming the LVL in place we were able to transfer that sagging roof load to the beam on to the posts and down to the foundation. This solution also prevents further damage to the sidewalls.
It would have been ideal to lift the structure back in to position but in remodeling and repair there always has to be a cost-benefit analysis of solutions.