How can I improve this roof

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  #1  
Old 09-04-20, 01:24 PM
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How can I improve this roof

I have a roof over a basement stairwell. The shingles need to be replaced so I am planning to go out there and replace them. But this is an opportunity to possibly improve the roof. So is there anything I should do besides replacing the shingles?

I've only repaired one roof in my life - a garage roof. With a house there may be more details you have to get right. For the garage, it was just ripping off the shingles, replacing rotten wood and slapping new tar paper and shingles on, and adding a bit of flashing where needed. Not complicated. No vents, no gutters, no other things to install. However to repair this house roof, there might be things I'm not aware of that I'm supposed to install. For example do I need a moisture barrier?

It's basically a flat roof with a slight slope. There is flashing underneath the shingles near the edge; I won't know if the flashing covers the entire roof until I rip the shingles off. I assume the flashing doesn't cover the entire roof and the roof is plywood. I think water and snow is seeping in somewhere, I can't determine where exactly, due to poor condition of the shingles and lack of caulk/flashing/foam at joints, and there may be damaged plywood and flashing.




Can I insulate the top of the roof? I mean underneath the shingles, on top of the roof. I don't mean insulating the interior of the roof. Some research tells me it's possible if I attach shims so air can circulate and moisture can escape. But if I do that, apparently I'd have to add vents. Where would I put these vents? Wouldn't vents defeat the purpose of keeping warm air in and cold air out? As for insulating the interior, more research tells me you're not supposed to attach the insulation directly to the wooden ceiling - again, you're supposed to leave air space and vent it somehow. This goes against everything I thought I knew about installing insulation - that you glue the insulation panels to the wall and then attach drywall over it to the studs - no air space. You even caulk the edges so nothing gets in or out. Is it different for ceilings, or are you not supposed to glue insulation to an exterior wall either?
 
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Old 09-04-20, 02:48 PM
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I would consider adding more slope to the stairway cover roof by increasing height at high end or lowering the height at the low end or both. Water that freezes within shingles will destroy seals between shingles as it expands and over time will leak onto the sheathing. Make sure sheathing extends beyond the walls so the rainwater coming off the roof doesn't collect at the base of the walls. Is there a foundation for the 3 walls? Not sure why you want to insulate since there is no heat and you want to add vents. Aluminum rectangular vents can be purchased at most hardware stores, Get ones that fit between studs in the wall.
 
  #3  
Old 09-04-20, 04:07 PM
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The reason it's likely failing is the lack of a proper slope.
A roof with that little slope should have had a metal roof.
 
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Old 09-04-20, 04:32 PM
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Look up the specs/instructions for the shingles you are considering. Most specify a minimum slope. Many consider a 2:12 pitch the absolute minimum but I prefer to see closer to 4:12. If you have a pitch less the minimum for asphalt shingles then you need to choose a different roofing material.
 
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Old 09-04-20, 04:56 PM
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install some type of metal roof and the slope issue will go away!
 
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Old 09-04-20, 05:54 PM
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Thanks for the replies. I have considered putting in a better-quality roof material, like metal as some of you suggested, but it's not common around here. Every roof is shingles if they're sloped or gravel & tar if they're flat. I don't know if any local contractors do metal roofs or if the roofing material is available to the public. I've never seen it at Home Depot or any other store.

I inspected the basement entrance. It's not level. It's leaning over a bit. There are issues with that since the retaining wall is separated from the interior door frame in the basement itself. The foundation floor of that area is also tilted and cracked. I doubt it was like that originally. I guess the builder, 100 years ago or whenever, didn't build a proper foundation first, and now it has shifted. I don't know if this is a serious structural issue, since there's nothing above that roof, but water is often on the floor where the retaining wall has separated from the door frame. I could fill in the gap with new cement, from the inside, but would that really solve the problem? Maybe it would make it worse? Previous owner(s) noticed the same problem and tried to fix it by filling the gaps with foam spray and polyfilla... neither of which is working out so good. The water finds a way in anyway despite there being pavement surrounding the entrance. I have sealed off any gaps between the pavement and the exterior with tightly packed cement, and/or new asphalt, but water is still coming in somehow. It's not like there's an obvious water source. I don't know where the water is coming from. Even if I used proper cement to fill the gap inside the entrance, it would be a temporary fix if the problem is on the outside. So I'd have to at least dig up the driveway and patch the retaining wall from the outside. At most, dig up the driveway, tear down the basement entrance, lay a proper foundation, and build a new entrance.

Maybe the water on the ground inside the entrance is coming in from the roof, because of the poor condition of the shingles. Or maybe water is getting behind the siding and dripping down. I don't know. I even go down there and look sometimes when there's a rainstorm or snow is melting, but I can't figure it out.

My point is it might not be worth it to put on an expensive new roof or to rebuild the roof with an improved slope if I'm going to have to have the entrance torn down and rebuilt eventually. I will get some advice on whether to tear it down. In the meantime, the shingles are toast and have to be replaced. I already have shingles to use.

re: beelzebob - I'm thinking of insulating it to stop so much heat from escaping. It gets really cold in there in the winter and the cold air gets into the basement.
 
  #7  
Old 09-05-20, 06:15 AM
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Consider insulating basement door, outside and inside.
 
 

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