This roof covers a 13 x 22 foot addition to my nearly 100 year old house. Slope might be as much as 1/4 in 12. Present roof appears to be maybe 3 foot wide sheets of metal, tarred where they overlap. I’ve been patching it for a while but would like to fix it for ‘good’, and I hope, add at least some slope. I found a little information in the archives about tapered foam. Would appreciate thoughts about whether this would be a good idea, what material to use over it, and how best to deal with areas where this roof meets the old roofs.
Thanks.
Thon
Replies
Hw much snow load do you get? How about just a straight-forward EPDM or PVC membrane. Shedding water does not require much pitch.
PVC membranes don't have a very good track record on roofs
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If those trees we can see the shadow of overhang the roof then maybe rubber isn't the best way to go either. How about torch-on? It's pretty tough stuff.
I think of torch down modified bitumen as not appropriate for residences or for DIY installations. It is more of a warehouse roof product. It is definitely tough, but two major considerations for a DIY. One - The temp of the torch needs to be just right for longevity of installation. The temp is a judgement call based on experience. Two - Think about how easy it can be to start a house on fire with that torch! [ "Don't ask me how I know", Piffin said, with a sheepish looking grin ]
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Piffin,
I agree with you completely. Torch-on is not work for an amateur or even for the self-taught.
I set one on fire once, myself. I blew the flame into a gap between boards on the wall above the cant strip where I was torching down the last piece and it set some old rotten bits smouldering. I shot most of 10 pound dry powder extinguisher into it but it seemed to blow the fire in further rather than putting anything out.
Call the FD. They arived in about 2 minutes, passed up some axes and we started to take things apart. There was no open flame, but, in 15 or 20 minutes, the fire had moved through old dry rot to an extent that would blow your mind.
I was shaking, but the firemen were joking and laughing about this because there was no flame, no danger that anyone would get hurt or that the fire would get out of control once they got to the job site. We got it in time.
What's your story, or should we start another discussion?
Ron
Similar.
I had been schooled in how to and had done several torch down jobs.
My attitude then and now was that the product was developed to market to handymen types and low budget roofing outfits without the investment in equipment that it takes to do true BUR roofing. Carpenters and shingle layers doing the occasional porch roof, etc. So I only used it when asked to.
So it was about fifteen years ago now, shortly after moving here, and having sold my kettle and stuff that my new employer had me using the torch on a porch that tied into the house only a foot or so under the eave of the main roof above.
The overhanging soffit was apparantly not caulked tight and squirells had quiet a nice nest of debris in there. I was proceding with a careless attitude that day based on the fact I disliked the stuff and just wanted to be done. so it caught the fire and smoke started rolling out the ridge vents. I killed the torch and grabbed the eave trimm and hauled up, fired myself by adrenaline, and stripped a section of shingles by bare hands, screaming for a hose all the time and hoping someone in the neighborhood could here me.
My boss and his brother just happened to be cruiising by at the moment and one said to the other, "Do you suppose that smoke is supposed to be there?" So they rolled in and passed the garden hose up to me.
ended up getting the shingles back on by dark - I had to do something with all that excess adrenaline.
;)
The boss decided the next day that torch down roofing was not part of his bag of tricks anymore. Actually that was when he announced it. I think he made the decision over supper the night of the fire.
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"PVC membranes don't have a very good track record on roofs"
Interesting. I inherited one, I think. A very heavy white material with some sort of reinforcing mesh embedded in. Does not have much stretch, and impossible to tear. Seems popular around the Portland ME area. That's PVC right? How do they tend to fail?
the problem was this - The pvc would warm up and gasses under it would raise a blister or bubble. That would then catch the wind and the unadhered membrane would lift more, rolling the ballast away, until you had a balloon. Looked like hell, made noise and stresses from the stretching would wear it out quickly - if the wind didn't tear it right off. I didn't even know there were any PVC products left on the market for roofing.
It could be that they found a way to improve it by adding the mesh you describe to give it some dimensional integrity, but the other problem they needed to overcome was that UV solar rays would make PVC brittle faster than most other roof products.
Another roof product similar to what you describe was a polyester fabric tjhat was applied with layers of cold process goop of various kinds, the best of which was an elstomeric rubber. Does yours look like it was a fluid applied in place - evidenced by imperfections and pooling or puddling and striations?
In general, the EPDM is a far better value than most other roof products for flat roofs.
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EPDM would probably do it. Don't know about the contoured foam.
jt8
Yep, EPDM seems to be the best solution without getting into a meduim/lg scale remodeling project to change some rooflines around.
TAB,
The purpose of ctapered foam for roofiong is to introduce a pitch where none exists, generally on commercial projects with interior drains. Not necessary here on yours at all. You seem to have adequate pitch. 1/4"/12" is a standard requirement for these.
The biggest problem you have is that flat metal stock never is, was, or will be and acceptable method for roofing an are like this. It has been common in the past to use soldered copper on smaller roofs but an are this size will have too much thermal moverment for those joints and I assume your joints are cualk ond nails. Looks like an ameture solution to me.
The only question is how much you want to spend and whether you want to do it yourself.
There are products (Polyglass is one available her) t6hat are a peel and stick membrane with a surface similar to that on the shingles. The adhesive quality is like the ice and water shield products and there is a woven re-inforcing mat contained within the membrane. The rolls are about 39" wide - metric sizing.
The better product is EPDM rubber roofing, but it is a bit more technical in metjhod of installation and flashings. Carlisle sells to homeowners.
Regarless of the surfacing membrane, I would definitely recommend that you rework the edge trim on that addition. you need a 1x2 drip strip of wood over the facia and a metal trim designed to shed water out away from the face. As it is, the water is dribbling down over the facia and destroying it.
Also - be VERY careful around that service entrance and gutter there. It is hard to imagine that this is a safe situation and I wonder how well that drip loop works on that entrance.
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It has been common in the past to use soldered copper on smaller roofs but an are this size will have too much thermal moverment for those joints.
I just finished one 50'x16'. Ran an expansion joint down the middle and treated it like two 25'x16' roofs.
Nothing like an expert to solve a problem. I never thought of that. largest I'd seen was no more than 12-14 feet in any one direction.
bravo
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Thanks for all the responses--very much appreciated.
<The only question is how much you want to spend and whether you want to do it yourself. >
Yes I'd like to do it myself. Plenty of time, and generally enough energy. <g> I want to spend just enough that I'm not up there in the next decade (?) fixing leaks.
Snow load used to be significantly more, here in central KS, and who knows, may be again. There ARE a couple of small areas where water does pool, which seems like not a good thing. From just a physics standpoint, I'd think the more pitch the better, as long as it doesn't interfere with drainage from the intersecting roofs. I am somewhat familiar with EPDM and have seen your references to Polyglass before, and had figured I will use one or the other. My main concern was would it be best to change the pitch, and if so how? I had thought it might not be too complicated to raise the height of the lower roof (on the left side of the pic) so that it matches the point where the shingles end. Then, from that point, continuing to the right side of the roof, building up as needed, to essentially have a shed roof. True it wouldn't be enough pitch for shingles but it SEEMS it would be significantly more than is there now.
Yep, I'm aware of the need for a drip edge, even if the amateurs who did the roof weren't. <g>
<Also - be VERY careful around that service entrance and gutter there>
Actually the service entrance is on the far side of the roof, and several feet away from it. What you're seeing is a line to a shop that I can easily disconnect with the breaker. And I am VERY respectful when I'm around electrons.
Thanks again.
Thon
(Hammer, you kind of lost me there. )
I went to the Carlisle and Polyglass web sites and found MANY products and no good details about exactly which of those products would be most appropriate for my needs. I think they both have distributers is KC, and I can talk to them later in the week when I'm there, but in the meantime if you've a specific product in mind let me know and I'll research it some more.
Thanks.
Thon
You're right, the web sites are terrible for consumers, especially carlisle.
fort an EPDM, you are looking for .60 thickness. ( another company that I have heard markets to consumers is Mulehide and others advertise in the rear bages of FHB)
The polyglas I have use is a mineral surfaced peel and stick similar to ice and watershield. I dion't buy online but if you take descriptions like this to your local lumber yard, they may have a supply of similar to sell you, or can get it.
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Well Tab, you certainly have a tough area to deal with. Presently you look like you have a dish in that flat roof. Going on the basis of looks, I think I would run a shed roof. You have a bit of a shed roof now where it meets with the flat roofing. I'm guessing you could run rafters from the outside of the addition so that they just come even with the crown molding on the fascia and continue until you intersect the shingled roof. It looks as if you will be going up almost parallel with the short section of shingled shed roof. Where the roof juts out passed the door you could do a standard gable from the mid point of the addition up to the shed rafters. I don't know if you will be able to get enough pitch on that backside for shingles but you can use double coverage roll roofing. I would also cover everything with a bituthane product first. You will have to cut in dormer flashing when you gable over the door area. You will have some space for insulation too. Hope this makes sense. I would avoid adding anymore valleys in that area and try to give the water a smooth flow. I would go up there with long enough 2x8 and see if what I described will work. You will have to do some marrying in the valley but it doesn't look like much. The most work will be where the gable cuts into the house siding.
There are some rubber membrane roof systems that may work over the product you describe. Requires professional installation
If it was my place, I would rip off the existing roof and expect some problems underneath. You will have to spend a few bucks on this one but you shouldn't have to worry about it again for 20-30 years.
Is this close to what you were thinking? The only "bad" detail is where the second floor roof would intersect.
Could narrow that overhang a tad on the right hand side to get a better intersection to the upper roof.Occupational hazard of my occupation not being around (sorry Bubba)
Nice job Capnmac. Yes, this seemed to be the most straight forward approach. There are three spots that need some special attention. 1. The valley, 2. where it intersects the existing soffit and 3. where some step flashing and trim work are needed to the left of the door as the rafter meets the existing wall. All these areas are small but you need to know how to make them weather tight and blend with existing conditions. Looks like a fairly simple job but I suspect there is trouble in the existing flat roof, that may mean a new ceiling inside. Gutters might not be a bad idea too, there will be a good amount of water coming off that roof.Beat it to fit Paint it to match
Looks like a fairly simple job but
LoL! Don't they all?
Don't give me too much credit, I was just was trying to follow what you were describing (and started drawing on the existing photo).
I'm second guessing returning the slope on the "leg" of the El (the bit in red)--but without actually being there, that would be a judgement call. I have this "reflex" to bring that shallow "wing" form out to make an entry (and also be an excuse to clean up the service to the outbuilding).
Pergola, no I am not thinking about a pergola. I am not thinking about a kinkaju in Denmark, either . . . <g>Occupational hazard of my occupation not being around (sorry Bubba)
That looks like an elegant solution, but also seems considerably more complicated than just making a shed roof--at least to someone who doesn't frame roofs for a living. It would drain to the right, the way most or the roof now drains, and would essentially follow the blue lines in the pic, but they would intersect the old roof where the shingles meet the flat roof. Any significant problems with this idea?
Thanks.
Thon
Thon, I think going with where the shingles meet the flat roof now, won't change your pitch. It won't address the area over the door, which pitches the opposite way, unless you build that wall a little higher. You will have to deal with the area at the crown, either way. Personally, I would go for as much pitch as possible. Even with what I suggested, you look like you will still be fairly flat. Sometimes we have to pick our battles. If what I proposed is beyond your comfort zone, I would not recommend tackling this job. My idea is quite simple, maybe too simple, and requires only basic roofing and carpentry. Depending on the actual length of that span, king pins or another form of support may also be needed for the new rafters. As I said before, I am more concerned that the failing roof you now have is a fix for a previous failure. When you get it open, expect some trouble. Getting it up higher will afford the opportunity to get some decent insulation up there. This will reduce heating bills for that room but more importantly, help to prevent ice build up and the ensuing backup of water. This is only an idea based on a picture. Actual conditions may dictate a different solution. I figure you have had enough of the nuisance, not to mention, it looks rather rinky-dink compared to the rest of the house. Good luck.
Beat it to fit / Paint it to match
tab_a
i had a customer with the same problem. my solution was to build a standard wood frame roof with i think about 3/12 pitch if i remember right. ran a 16" lvl right to the top of the valley for a hip then ran my rafters to the existing over hang. it got a little funky in places but in the ned it worked out fine.
i also removed the most of the existing roof underneath to repair rot, before framig the roof . on top of the sheathing i used weatherguard and 40 year shingles.
the old roof was moped on with rocks on top. waht a nightmare for the owner.i musta gone up their 5 times with buckets of tar to try and repair this roof before i suggested framing the new roo as these were an older couple with a fixed income.
needless to say they havent had a problem since.
the addition was put on by an out of town firm whos doing another project on the island at the time.
tyke
Just another day in paradise