this building is a sectioned facility that was built in the 40s with terrible engineering. pitched roofs angle into flat roofs, meaning nearly the whole 40,000 sqft facility channels water off onto two sections of roof, creating a cascading waterfall for about a half-a day after the rain stops.
the main portion that leaks all the way through is down the front wall where the parapet is on the front of the building. water leaks down the bricks and keeps the wall damp nearly all the time.
we brought in professionals to assess and suggest solutions (other than replacing the whole roof, which would be in the several hundred thousand dollar range to do). they suggested Titex fabric w the layers of petrol-based binder and topcoat. it is more of a spot-repair, but on this kind of roof we are uncertain where the leaks originate. we repair where the water comes in (the parapet corner) but it has yet to stem the actual leaks.
so i am trying to come up with a perhaps unconventional solution.
one idea was to maybe cover the whole flat section w a second roof of corrugated metal at a very slight pitch to keep water running off. securing it would be a big issue without tearing up old roof, and it wouldn’t stem the seeping leaks.
now i am thinking about that waterproofing rubber spray, or even spray-on bedliner.
as you can tell, i’m trying to think outside the box here. anyone have any crazy, good suggestions?
is there a conventional fix that might be easy that we have neglected to consider?
I am not sure just what was used but the machine room roof on one our buildings were almost flat with only a scupper drain on the side. We would have about 6 inches of standing water after a rain.
And underlayer was added to the roof to slope to one point. at that point a hole was drilled into the roof and a drain was put in. Then the whole roof was covered with normal roofing rubber.
Google and Youtube search the ‘liquid rubber in a can’ stuff I think you will see you wouldn’t want to trust it to keep a camels hump from getting wet in the desert during the dry season and a 100 year drought.
Bed liner may be a possibility, but for that I would be concerned if water did get underneath, hwat happens then?
Diverting much of the water away from potential leaks may be just the ticket. I have done this with a skylight that had a tendance to leak. One piece of Al flashing to divert most of the rain away has ensured that not enough water has made it to the potential leak spots so I don’t have to worry about it.
Get some of those really huge giant inflatable monkeys that car dealerships put on their roofs. Weight them down enough so they don’t float, and otherwise fill the flat roof with giant monkeys. That way, there’s much less water to have to drain off (like putting a brick in your toilet tank to use less water when you flush).
as it is, we have a dedicated sup pump where it leaks on the more important areas.
what happens is 1. all the water off the main section of pitched roofs drain to this flat portion while 2. all the other flat sections drain here as well* due to it being the facility’s low spot, 3. the building is old, it has leaked for years and the subroofing and trusses have all been damaged due to water, so this section of the roof is “flat” but far from level. meaning there’s all kinds of dips and low spots where water stands. *(water off the building ultimately drains in two main places; here and off the back of the center of the warehouse. both are high-velocity waterfalls for half a day after the rain stops. guttering would have to be something like small sewer pipes to catch it )
one of the worst sags was along the parapet, so we built that up w underlayment and put the titex fabric and overcoats there the most.
now water won’t stand there, but if you don’t pump off the rest of the water, it pools about 3 inches deep and seeps.
for this years i have used the pump, starting it whenever it rains. it will take around 8-15 hours to pump off all of it, depending on how much it rained. but, as an example to why this all sucks so much–yesterday we had storms for nearly the entire day off and on. so the pump couldn’t pump fast enough, everything kept wet, and hundreds of new leaks (and breeches in the old leaks) sprung up.
the whole deal is seriously frustrating; we go up and patch the shit out of the places where it drips through, yet it never solves the issue.
it was old tar-paper and hot-tar w those roof pebble rocks all over to start with. and has layer upon layer upon layer of repairs over the years, followed by more surgically precise titex repairs done by us.
what NEEDS to happen is the whole thing torn up, trusses repaired, new decking and new roof. but like i said, the funding would be unmanageable, this section alone was bid at $40k.
Other than an enormous tarp to cover the entire building, you’re fairly well hosed unless you manage to some day find the mother leak.
Flat roofs are just pure evil, especially the traditional ones that are made of a baklava of pebbles, tar paper and tar. The problem is that the layers either never bonded fully in the first place, or more likely, layers of patches didn’t bond so there are vast expanses where water is free to infiltrate the layers and seep sideways and downward. The actual topside leak is probably 50 feet away from where it’s manifesting itself inside.
If used car gorillas don’t excite you, maybe Goodyear is about to retire a blimp. Buy it, slit it end to end and drape the blimp skin over the building.
For spot repairs, Henry 208 wet patch is the best stuff you’ll find at the hardware store. You’ll want elbow-length gloves to keep it off of your skin, and turpentine to get it off of your skin. The last time I did hand-to-hand combat with this goop, I used a barbecue “mop” to slather it on while trying to keep myself as far away as possible.
Oh, start playing the lotto. You may have better luck raising capital for a re-roof there than with a bank.
funny about the tarp. i tried that. turns out tarps don’t weather too well around here. they get baked and turn brittle then kind of just break into dust.
i hate the Titex system. it’s a fiberweave fabric that has about the waterfastness of burlap. you lay down the adhesive layer, the fabric, and alternate coats of bullshit til you get to the black top stuff.
it hasn’t solved any of our problems. i want to do a rubber membrane, but they don’t know if it will seal to what we’ve been putting down.
plus those gross pebbles…
i worry about the weight of the ponding water on this old building. yeah it’s an industrial warehouse, but i think i care the most about the roof around here, and i have the most intimate experience w it. and there’s a lot of rust up there…
and we salvage antiques stuff. we need a goddamn dry space. frustration
so let me ask this: how would you secure a secondary roofing later, say corrugated tin, without punching new holes in the old roof and making shit worse?
i had this idea one night…it was raining and i looked at our pitched-roof outbuilding on the traintracks. it’s a large building with a bare metal tin roof. and it never leaks.
talking to the owner, we have access to antique barn metal (corrugated tin) and can come up w the footage to do my slightly pitched second roof idea. i just don’t know how i would secure it down from bible-belt storms and god-fearing winds we get around here.
Ugly Plan C - build your corrugated tin roof inside over the stuff you care about. You just jogged my memory of someone I knew who lived in a converted furniture factory and they put a roof of corrugated fiberglass panels over their ‘bedroom’ area.
No worries about securing it against the wind that way. You just need to finagle a way to carry the water that falls on it to the outside or a drain.
i live here, in this area is what leaks so bad (coincidentally, over my bed). i actually thought about building a medieval style tester bed with a pitched roof and guttering.
If your going unconventioanl, jack up one corner of the building so all the water runs down to the opposite corner. Put a downspout there.This might be past the last thing you try.