Q. We will be putting a new roof on soon and it will most likely be a lightweight tile one.

Q. We will be putting a new roof on soon and it will most likely be a lightweight tile one.

We currently have a heavy shake roof. Should we remove the shakes before the tile roof is put on or should the tile roof be put over the shakes? I have seen both approaches lately and am not sure which would be better.

A. It is strongly recommended that all of the existing roofing be removed before a new roof is installed. The wood sheathing below the roof is highly susceptible to fungus damage and dry rot that will continue to spread if left untreated.

Roof replacement is as excellent time to make a thorough inspection of the roof sheathing and make any needed repairs. This would be impossible if the new roof is installed over the existing roofing.

True, there is a cost attached to this, but, comparatively speaking, it is only a small part of what the new roofing job will cost. Besides, if dry rot does exist and it is not dealt with now, it could cost significantly more to make the repairs later.