Rolled roof install

[Sharpest]

I have a large metal building in need of reroofing. It is an old building, my family has owned it for 40 years, and the roof has never been touched. The frame of the structure is made out of drill stem and the arched roof trusses are made out of sucker rod. It has 2x6 wood perlins and the whole thing is sheathed with corrugated steel.

The roof is domed with corrugated steel layed over wood perlins just like the sides, but with a rolled roof topping. I cant recall the roof ever being touched in my life and it shows. The rolled material is completely disintegrated and falling off in sheets. This has led to drastic leaking throughout the whole building which is bad enough its damn near unusable when its raining. All of my **** is getting wet and the ceiling insulation and drywall in all the office rooms is ruined and will need to be replaced. It also doesn't help that a large portion of the roof is covered with several inches of detritus from the mimosa trees in the yard.

I got up there for the first time ever a few weeks ago and was shocked but no not surprised with what I found. Here's a shot of the length of the building from the very back edge.



Shitload of tree leaves and branches along with two trees that had grown onto and around the eve of the roof.





And a few shots of the general ****** condition







One major problem is that the sheet metal is cupping between the perlins. It is the worst at the peak but is bad enough that water definitely puddles there.

 

[Sharpest]

When I had a week off I went postal with the chainsaw and cut every tree branch that was hanging over the building as well as any that might start to hang over in the future. Ive been looking in to reroofing and my findings are fairly encouraging. Rolled roofing is the ghettoest and cheapest form of roofing available and as such is not used on the $300k+ houses I build, so I know jack **** about it. The good news is that a 100' roll of material is ~$40 and I will need 40 rolls or so. The arch length of the top of the building is 75' or so and each roll has 36" of width +4" of selvage for overlap. I will need to buy a nailgun that can shoot roofing nails through the sheetmetal. I also have no idea how much roof cement I'll need.

I've read that the rolled material should be applied perpendicular to the slope of the roof and overlapped like traditional shingles. My building looks like it was rolled over the arch of the roof, parallel with the slope. Anyone have a preference? I am seriously considering doing this job in two or three phases (front to back) to ease expense and effort so rolling over the arch would be slightly preferable assuming ultimate performance is the same. One other consideration is that I don't think the roof perlins are close enough together to anchor the nails in wood if I run it perpendicular.

 

[spike99250]

I have seen roll roofing running parallel with the slope many times, mostly sheds and garages. I have never applied it that way so don't know of any problems.
There is a self adhesive roll roofing available. Its sticks like crazy and have never had a problem with any roofs I have done with it. I have used it as emergency patches a few times over shingles.
You roof would have to be cleaned pretty good, and I am not sure how the corrugations would affect everything.

 

[djjsr]

There is a self adhesive roll roofing available. Its sticks like crazy and have never had a problem with any roofs I have done with it. I have used it as emergency patches a few times over shingles.

I've been looking for something like this. Do you know who makes it?

 

[CNGsaves]

Think you'll have to use giant 10 ft wide rubbery rolls of roofing material like commercial flat-roof buildings use. It's durable and somehow these fuse / glue the seams together so the whole thing won't leak. It may be glued on entire surface, but I did not see the crew while they were installing. Thus, I'm sure you'll have to powerwash all that loose stuff off, or maybe even fill in grooves of tin so roof is somewhat flat.

A couple big doctor's office buildings were re-roofed and they put down sheet styrofoam insulation first, then the big rolls of roofing material. The edges overlap the lip on outer perimeter of building that get secured with cap flashing. Top color is also white so the roof stays much cooler than old days when there was black tar roof up there. Good luck but it won't be cheap !

 

[readhead]

There are some spray foam products that are actually a finish coat and walkable. I see it used in New Mexico quite a bit.

 

[spike99250]

CertainTeed makes Flintastic and Henry makes Low Slope self adhesive roll roofing.
Cetainteed has a whole system of layers. I believe the idea is 1more money for them, 2 it would make it easier to replace the top layer down the road.
I have never used the different layers before but might on my house when the time comes. We have always stripped the roof and applied the roofing to the roof sheathing.
The Flintastic can also be coated so this would help extend the life of your roof.
Home Depot sells self adhesive roll roofing but I do not remember the brand.

 

[58Yeoman]

We had a small building at work (maybe 10x16 or so, don't know for sure) that has a fairly flat roof that leaked terribly (metal roof that is rusted). They patched the holes, then sprayed a foamy cover on it, then came back in a few days and painted it. Probably was't cheap, though.

 

[kbs2244]

Two thing I think you know you need to do is remove all the existing trash on the outside down to bare metal.
It doesn’t have to be shiny but it does have to be clean so your new material will stick to it.

Then you need to work from the inside and get a ridge support down the center to provide some slope and get rid of the puddles in those cups.
It doesn’t need to be a lot of slope, but you have to drain those cups.
I don’t care how much you spend on your roof, those cups will leak in time.

That is the reason they installed the roof with the grooves the way they are.
The panels would bend and fit the curve of the roof a lot easier if they went the other way.
But they would not drain completely.

 

[Zeke]

What a mess. I think I'd walk away from that. Get a big tarp for now and put a crew up there when the weather is good to pick it clean.

If I had to design a system I'd run the rolls perpendicular to the fall up 2/3 of the way up and then switch to the other direction for the top of the arch.

 

[Jim_No_Garage]

20 + Years ago we went with a spray foam roof with some sort of black coating on top of it. It was the new miracle roof material for large industrial buildings. It worked for a while but in the end it was an epic fail.

The lifetime guarantee was worthless when the roofer called it quits.

We lived with it for 10 years and ripped it off and went rubber roof torched together. Hasn't leaked since but was $$$$. This was on a 15k+ SF retail building.

Cheers

Jim