Is two layers of roof felt OK?
 

I am about to start to re-roof my house using the same fiberglass
standard three tab shingles. If I am able to remove just the shingles
and leave the 23 year old felt paper on the roof should I. Assuming it
is laying flat would adding a new layer of 15 or 30 lbs. (?). over it
plus the new shingles possibly cause any problems? I.E. moisture /
condensation or heaving? My thinking is during the project that it
might protect the interior from any rain even if I temporarily have the
construction area tarpped. Also even though it has nail holes it would
add a bit more waterproof coverage over the sheathing after the job is
finished not to mention less to go into the landfill.

Is two layers of roof felt OK?
 

My guess is that not much of the original roofing felt will be left
after the shingles are removed. As long as the nails are driven flush
with the deck, I can't think of a problem that would result from
leaving what's left. A lot of folks who should know don't think the
roofing felt adds much to the water resistance of the roof system. (Ref
Joe Barta & Building Science Corporation)
TB

Is two layers of roof felt OK?
 

Is two layers of roof felt OK?
 

Travis Jordan wrote:
wrote:
A lot of folks who should know don't think the
roofing felt adds much to the water resistance of the roof system.
(Ref Joe Barta & Building Science Corporation)

Unless of course the roof covering is tile, in which case the
underlayment IS the primary water barrier.

And, I should add -- one very good reason for having a semi-permeable or
impermeable moisture barrier between the roof covering (ie: shingles)
and the sheathing is to prevent any condensation that forms on the back
of the shingles from dripping onto the sheathing. And I think all
current shingle manufacturers require an underlayment layer, as do many
state and local codes.

Is two layers of roof felt OK?
 

Folks around here use a lot of "wrinkled tin" as roofing.
I am now suggesting they use one of the "rubber" sheets.
TB

Is two layers of roof felt OK?
 

i think the primary function of felt under three tabs is to prevent the
shingles from adhereing to the deck. i once inspected a roof that
didn't have felt. the shingles were cracked along all the plywood
edges.

Is two layers of roof felt OK?
 

tar paper or a much better choice rubber impermable membrane is a
essential part of the keep dry system.

blowing rain can get under the shingles and cause a leak. this happened
to my travel agent her home builders kids crew didnt remember the tar
paper, after numerous roof leaks and insurance dis owning the water
damage it finally got fixed had to replace roof.

other things to do when replacing roof, REPLACE flashing everywhere,
covers around serer vents, how about ridge vent upgrade, drip edge and
inspect all chimneys and chimney caps for cracking which can cause CO2
poisioning and death... lighter color roofs last longer and help keep
home cooler in summer, dark colors absorb heat.

Is two layers of roof felt OK?
 

Last few times I tore off shingles, the tarpaper got torn up pretty
badly and for the most part just pulled right off with the shingles
anyway. What was left was so wrinkled, torn, and bunched up that it
would have been a pain to try and flatten it back out. I just pulled
the rest off and started clean with new tarpaper. Lets you inspect the
deck anyway, which you should do while you have the shingles off.

-Kevin

Is two layers of roof felt OK?
 

Is two layers of roof felt OK?
 

lighter color roofs do last longer and they keep the attic cooler in
the
summer. However, studies at the University of Florida have shown that
if you have adequate attic insulation (R-30+) then the attic
temperature
has no discernable impact on the house's heat load.

Thats very likely BUT lighter colored roofs reflect more heat thus the
attics are cooler so the shingles last longer. I recently sold a home
with gable end and ridge vent. The home inspector wrote it up because
the attic was 20 degress warmer than the outside on a hot july day. He
recommended adding power vents to the roof.

Light colored roofs just make everything easier

you want a cool attic if your like many and use it for storage.

Is two layers of roof felt OK?
 

Is two layers of roof felt OK?
 

the home inspectors were a joke, had 2 home inspections on the same
home within a month of one another. the 2 inspections looked like 2
different homes.

the first inspection scared off the first buyer, sad because it was a
nice solid home

first home inspector wrote up no GFCI on sump pump, 2nd inspector wrote
up it was wrong to GFCI a sump pump. all sirts of stuff like this

I just couldnt win

Is two layers of roof felt OK?
 

wrote:
the home inspectors were a joke, had 2 home inspections on the same
home within a month of one another. the 2 inspections looked like 2
different homes.

That is generally my experience, too. Only once did I have an inspector
make a good call - he was concerned about a stairstep hairline crack in
an outside structural wall, and recommended a structural engineer. The
engineer took core samples from beneath the foundation and found a
vacant area most likely caused by decomposed organic matter in the
original fill dirt. Negotiations with the seller went much, much better
after that.