We have one layer of shingles on the roof and we’re thinking of switching to tin when we need a new roof. We’re getting conflicting opinons from local builders as to whether we should lay the tin over the existing roof or rip the shingles off first.
I’d appreciate hearing what you guys think.
Thanks,
Judy
Replies
We'll, I've certainly seen tin over shingles on a number of falling-down barns. Not sure whether that's a recommendation or not, though the roof did apparently outlast the framework.
A little more seriously, I've seen a few cases where such a roof blew off in the wind -- the layer of shingles may make the roof more susceptable to blow-off. But again these were old roofs (why isn't it "rooves"??) and probably not all that well done in the first place.
I come from an area with lots of shingle roofs. I'm always in favor of taking them off for a few reasons:
- removal is fairly inexpensive compared with the total cost of the job.
- it provides an opportunity to be sure that the substrate is solid enough for roofing screws, and if there are repairs to do (which there often are), it is easier to do.
- easier installation of flashing and I&W shield.
Can not think of a reason to save an old roof
The more roofing material left on a roof will hold additional heat due to solar gain. A 2000 square foot roof with asphalt or fiberglass shingles holds a substainsial amount of heat for a long period time.
In the summer months it will take a lot longer for the roof to cool as well as the attic space below. If the attic space is insulated and vented properly this is not as much of an issue. Where I live this is rarely the case in the older homes.
Removing the old shingles is a very small cost in comparison to the cost of a new roof
Paul Z
Can not think of a reason to save an old roof
The more roofing material left on a roof will hold additional heat due to solar gain. A 2000 square foot roof with asphalt or fiberglass shingles holds a substainsial amount of heat for a long period time.
In the summer months it will take a lot longer for the roof to cool as well as the attic space below. If the attic space is insulated and vented properly this is not as much of an issue. Where I live this is rarely the case in the older homes.
Removing the old shingles is a very small cost in comparison to the cost of a new roof
Paul Z
I'm with Scott in saying that you need to take the old roofing off to check the plywood below.
Tin???
When you say tin, do you mean Tin, of do you mean a metal roof?
And specifically what kind? The manufacturers DO have recommendations how to install their products!
IF you leave the shingles in place, do NOT apply the metal roofing directly over them . Prep first by using furring and install to the furring, if the manufacturer allows that
Thanks, all.
Points all well taken...appreciate it.