Roofing question

I am stripping the old shingles off and applying a new layer. What does everyone use for underlayment? The roof pitch is 5/12 - I do plan on using an ice barrier on the lower edge. Always before I used roofing felt/tar paper for an underlayment for the rest of the roof. Menards guy tells me everyone uses synthetic underlayment - easier to use, lighter etc... He said the area roofers buy the cheapest stuff available - he recommended buying a "mid grade" for something that would last.

What is everyone else's experience?

ice and water seal on the entire roof .

I second that Buick.
Cover the whole thing in ice & water shield. Especially older houses with shallow pitch roof.

I've done a few and always used regular tar paper and had good luck. I use valley tin as well.

i still use 15 lb felt

The new stuff is far better than felt. You cant tear the synthetic stuff and it doesnt wrinkle up with a dew.

shame on menards for selling cheap stuff. roof and foundation are the critical points of a house.

(quoted from post at 13:01:25 09/05/19) i still use 15 lb felt

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I prefer 30lb. if laying flat, but the last 2 times I've bought felt roll, it's been all stuck together. Bought different times from different stores in different towns. I think I'd try the synthetic rubber next time.

(quoted from post at 13:19:45 09/05/19) shame on menards for selling cheap stuff. roof and foundation are the critical points of a house.

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Nobody forces the roofers to buy it there. If Menards didn't have it they would go down the road and buy the cheap stuff elsewhere.

I still like the felt and my son that used to build houses prefers the synthetic. Redid my roof a few years ago and I used both. Felt on bottom and immediately put the space age stuff on top. It is tough and has a texture to it that you can walk on easily. Mine is 6 / 12. BTW, that stuff is expensive and heavy! Course I think 1 roll takes the place of 10 felt rolls.

I?ve read the rest. First where do you live? Is the space heated? Central Mn and I?ve seen several applications over 30 years. How critical is cost? If you can afford a better product it will likely pay for itself.

When the home owner isn't looking some roofers don't use anything.

I live in NE Kansas - the underside is not heated. Which is the better product? After doing some research I've found that some brands (no one is willing to name names) of the felt are pure crap - just as well use the pink stuff that looks like paper grocery bags. I was wondering if anyone had tried out the synthetic.

I have seen synthetic used on both residential and commercial jobs I?ve been on as well as residential applications I know of from friends and enemies. It seems to be good stuff. The fact that it is a shed roof makes a difference because of heat and venting. I spent 15 years in the residential game and seen varying results from various products. No roofing material is what it once was because all the good stuff is bad for us. I don?t know the cost of synthetic v. Tar paper, but personally would not be afraid of synthetic. The pink stuff is red rosin paper and is meant as a buffer between wood floors and sub floors. Not for roofing applications. The last generation put it behind wood siding as well, they also would use tar paper in that same application. Because you are in a fairly mild winter climate area ice-n-water on the bottom and synthetic on the rest sounds sensible. The fact that I have a 120 year old corn crib in central Minnesota mean I fight a different battle. The story and a half knee wall with hand framed rafter doesn?t allow me adequate insulation or more pertinent adequate venting. If you are not heated, have an open attic, and can vent enough it will prevent moisture and heat build up under your roof/ shingles and won?t rob them of life. I?m gonna get grief for this, but when we reshingled the old school house at Junkshow we did not use tarpaper. We took off cedar shingle and reinstalled cedar shingle using half lap on each row applied to spaced oak roof boards. Why. Because a fellow club member and long time carpenter had recently tore off 2 year old cedar shingles applied over a fully ice-n-water roof deck which didn?t allow it to breath and the cedar rotted from the underside.

buickanddeeere,

You may wish to cover all that ice/water with tar felt. It will be easier to remove the shingles next time. Shingles tend to glue to the ice/water, bubt not to felt. I had to cut roofing boards off due to that "glue" effect, shingles stuck to the ice/water.

D.

If you look at those old buildings with cedar shingled roofs - there isn't any tar paper on the underside of the shingles on those roofs. If they lasted 50-80 years that way who am I to second guess.

A mid range synthetic costs about the same as felt.

I'm sold on synthetic felt. The synthetic felt is like a poly tarp on a roll. It's strong and long lasting. This helps if you are doing the roof by yourself and takes a long time. Regular felt will draw up and wrinkle and tear at the nails if you are taking weeks to put a roof on where the synthetic felt will stay reasonably flat.

Synthetic felt.

The width of ice barrier depends on your location, and also do the valleys.

If the building is not heated there is no need to use ice and water shield above one strip at the eves.

You are correct on that.

I 2nd this. We put ice shield in the valleys, and also on the 1st course if the homeowner requests it, but we always put paper on top of it before shingles. The next roofer will bless your children and grandchildren for that! We also use synthetic paper now. 10square to a roll instead of 4. Doesnt tear, easier to walk on. It actually tightens up over night instead of wrinkles in the dew like tar paper did. It's more than tar paper but job cost wise it's not really adding a large percentage. We use Atlas brand Summit180. Supposed to be good for 180 days uncovered in the weather. But I recently tried the lower grade summit60 and it was fine too. Our roofs are usually only open less than a day, but it's nice to know if shingles ever blow off theres something good underneath for a bit.

You learn a lot about problem areas when tearing off old roofs. Here in Maryland, when we find rotten wood at the bottom of the roof, the previous shingles had always been started flush with the drip edge. The water rolls around the shingles and wicks up into the plywood. We overhang the bottom shingle course 1 1/4". 95% of the houses we are roofing are on their 2nd or 3rd roof now, no ice shield before and no problems. Different climates may be different, but that's here. We always make sure the attic is getting airflow too, to get rid of any attic condensation.

That's a good point Dennis. I hadn't thought of that.

Using "ice dam" underlayment over the whole roof is getting to be popular around here, but would surely be overkill in Kansas. That stuff is self sealing; you can drive a nail through it, then pull out the nail and it won't leak. Definitely use it in the valleys as well.

It's my understanding that felt is used not so much for water resistance as to get a class A fire rating. Presumably the synthetic stuff is fire resistant as well. I've only used felt, but I'm sure going to try the synthetic stuff if and when I do another roof. One of my peeves about felt is it will curl up if it gets wet and dries, making it impossible for the shingles to lay flat. I assume the new stuff doesn't do that.

No valleys on this roof.

I was fixing to buy a house once, roofed in Cedar Shakes. The roofers were doing an house next door and I walked over to have a look. Standing in the house and looking up, I could see blue sky every other roofing slat. Apparently there are 2 layers to the gapped slats and the first layer is flat wedging and the top layer is grooved for appearance.

As the story goes, rain makes the cedar swell and it seals off the roof. Otherwise you can get in the attic and see through the roof. I passed. Told the builder I want my house with a composition roof. Never heard anybody gripe about a shake roof leaking and in the Dallas Metroplex there were loads of them over the years.....till the Fire Marshall banned them as a fire hazard.