# Reroofing over existing shingles



## tinner666 (Mar 14, 2005)

From what I've seen of shingling over an existing roof, the new ones deterioate pretty fast. I wouldn't do it.
And if I was going to do it, I sure wouldn't put felt under them. Instead of an 8 year roof, you'd probbaly have a 3-4 year roof and you get to tear two layers off then.
Not last, nor least, you won't be able to inspect the flashing, decking, etc, for any potential issues there.


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## Slyfox (Jun 13, 2008)

I have installed dozens of layovers with 3-tab shingles that have lasted 20 plus years.

If you go to the shingle manufacturers website "manufacturer of the shingles your installing" you'll find installation specs there.

The longevity of shingle lay overs is the same as new construction or tear offs, meaning the workmanship of the installation is what determines the quality/longevity.
Far as how long they'll last depends on regional weather conditions, slope of the roof, etc.

(Normally no felt is required)


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## sippinjoes (Mar 7, 2011)

Ripped off a lot of lay over roofs and never saw felt between the layers, just at the decking level.

Not fond of laying over, but that was because I worked for a company that always tore off which is a pain for many reason including making heavier work lifting multiple layers.

The problem with lay over is you don't get to inspect the decking properly. I don't know of any horror stories from not inspecting, so take that with a grain of salt. However, we tore off some roofs that had early signs of deterioration in the decking where walking over it would not have necessarily revealed the damage.


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## Roofmaster417 (Jun 9, 2010)

I try to talk my customers out of recovers.But in our economical situation,a guy has to do what he can.Most manufactures will tell you its not necessary to install felt over an existing roof prior to recovering.

When a recover is installed the idea is to have the recovering shingles to seat as evenly and firmly as possible.That will help your new roof conform to the shingles being recovered.

When I recover a roof I replace all roof accessories ridge vents,roof vents,pipe flashings,step flashing on chimneys,walls and skylights.Replacing these components IMHO will help with the life span of your roof system.

So I would replace all accessories and not use felt.


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## iamrfixit (Jan 30, 2011)

New shingles over sheeting lays so much flatter and looks so much better than an overlay job. The shingles you are covering up have to be in good condition, any curling or other defects will transfer right up through the new layer and your new roof starts looking old quickly. The reason most people want a new roof in the first place is because the roof is shot, that means it is usually NOT in good condition. If I am going to all the work and expense of a new roof, I want it to look like a new roof.

Don't ever see felt over the old shingles.


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