I am currently having a roofing contractor replace the roof on my home. I noticed when they first started that they were putting down felt between the sheathing and the shingles. The job is about 80% complete. So, I decided to inspect there work the other day and found that the garage and a side room did not have any felt under the shingles. I immediately called the contractor and asked, why? His response was that if there is a possibility of rain he will put felt down for his protection. However, if the weather is good then no felt is required. I didn't like his answer. My opinion is that felt is required because it acts as a water barrier (it just makes perfect sense). So, do roofs requie felt? Is there a roofing requirement/code which states that all roofs must have felt?

 

there is about 47 differant answers to your question but in my opinion you should always use felt.But--- you could say what good does the felt do when you nail it down just gets poked full of holes...there goes your water barrier idea.anyway we always use it and try to use 30#if the budget allows

 

In the past, most roofing manufacturers did not REQUIRE felt under the shingles. The shingles would still carry a warranty against mfg defects, regardless if felt was used. So your roofer is not TOTALLY incorrect.

There are 4 main reasons to use felt.
1 - To give the roof temporary protection against moisture (rain) before the shingles are installed.
2 - To separate the shingles from any NEW plywood decking. NEW plywood has oils and resins that manufacturers don't care for under their shingles.
3 - To allow the shingles to "breathe", giving them better longevity.
4 - To give another layer of protection (albeit not much with all of the nail holes) under the shingles in case water happens to get behind the shingles.

Recently, most, if not all, roofing manufacturers have decided to "require" felt under the shingles. You may want to look at the wrapper.

I personally would always use felt, but there are still plenty of long time roofers that have not used felt all the time. I would use #30 felt under heavy weight (or laminated / dimensional) shingles and #15 under 3 tabs. The 3 tabs are typically not heavy enough to weigh down any imperfections (ie waves) in the heavier #30. The imperfections in #30 felt will "telegraph" through a 3 tab shingle.

Now CODES are a whole different story. If you live near a coastal area, there may be wind requirements, fastener requirements, felt guage requirements, or other nagging requirements. Deed restrictions in your neighborhood may affect this as well.

I would check for any local requirements or restrictions in your area. I would also look at the wrapper of the shingles that were installed. It should give a recommendation for felt use.

Good Luck.

 

nomad===one of the things i like best about 30#is how flat it lays.so....just my opinion

 

I agree. #30 does lay better.
Unfortunately, I haven't seen many roofers who actually install it correctly. Most of the time it sits out in the weather too long or the roofer doesn't give it a chance to relax and he nails it down with wrinkles and waves already in it.
Either way, many roofers put 3 tabs over felt that is already wrinkled. Not a practice that I care for.
It's nice to know that there are still installers out there that take pride in their work such as yourself.
Keep it up.
Thanks.