My brother owns an apt building (aprox 52’x105′) with a series of leaks in its flat roof.
Apparently, the roof (I have not been up there) has six “gutter boxes” around the perimeter of the roof that goes out through the walls around the perimeter to down spouts.
Over the last year he has had several commercial roofers patch the leaks and most have suggested replacing the roof to the tune of $40k+ (Columbus Oh $’s). They do not want to put a specific bid together due to not knowing what is in the support structure and its condition.
In reality, that is a lot $$ to put into this building, maybe too much. We have been talking about other ways to solve the leaks – an overlay roof?
To complicate the problem, we are in a historic district so anything we do needs to be invisible from the street.
He asked me if I thought a low rise (between 24″ and 36″) truss roof, supported from the edge of the roof and two points where the central hallway walls are located might work.
I know that I am dancing way out there but is something like that even worth spending a lot of time trying to get approved by the city, and likely to have enough slope not to allow puddles and really solve the problem in the longer term?
Collection Boxes would define the lowest point of the roof I suppose, here is a picture of the wall with one of the boxes:
Thanks for your thoughts….
Replies
OK -here'sthe terminology I use: The passage thru the wall is a scupper. The collector box is also known as a leader box.
From your picture, it looks to me that the collector box is too high. It should be positioned so no water will back up thru the scupper if the downspout is clogged, but instead run over the top of the box.
The commercial roofers should be able to cut a core plug somewhere in the roof to tell how many layers are there and consequently how much it will cost.
As far as some sort of overframing and consequently roofing that, I can't imagine you could do that for any less than $40K which sounds about right for recovering and installing EPDM or modified. There's probably HVAC units on the roof as well as lots of other penetrations and parapets all the way around to flash.
http://grantlogan.net
Who got Bo Diddley's money?
That building is considered historic?
Oh boy! A serial leaker!
Grant already took the rest of the words out of my mouth. If your brother isn't ready to pony up and pay for the ride, he will continue to go from one roofer to the next for repairs all while the building gets soaked and ruined while costs go higher and higher.
cost of roofing goes up every year, but he adds not only the annual inflation to his outlay, but the cost of repairing the structure that he is letting get damaged by the leaking. Add to that eventually the cost of the liabilities he incurrs by negligence. I've seen it a hundred times. The new roof will never be cheaper than now
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BTW, new roof can be applied with tapered insulation base system that avoids puddling.
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Is that a drain above the window?
Why is it lower than the leader box? different roof height?
First off, we are in a historic district (Columbus OH - Olde Towne East). The building is under the jurisdiction of the building dept as well a historic preservation office. Some of their rules are dumb. When he bought the building, he wanted to replace the windows. Sure they said, just make sure that they are energy efficient, but not vinal, and they need to match the existing ones. Not a problem they said. Just do it our way. He passed after pricing out a single unit's windows.
I have not been on the roof, so I cannot state if the collector box is higher than the roof edge or not. Someone is supposed to climb up there this week and get some pictures, I will add the collector box and scuppers to the list of measurements ans photos.
No HVAC on the roof (through the wall units), but I can think of at least eight vent stacks and eight flues coming through (8 apts on each of two floors, upper and lower share flues and vents, but they may combined the eight vents into four just below the roof (I just do not know pictures will help).
Tell me a little more about taper insulation base. Does it require a tear off the existing structure, or the gravel? Will it make a significance energy difference?
Thanks,
Larry
Think about a spray on foam overcoat. It can be sloped as you like by varying the thickness. With a proper coating it will last a very long time and the building will be more energy efficient.Nobody gets in to see the wizard...not nobody...not no how!
I don't have much confidence in foam roofing, having never seen one that works for long. Again, those scuppers would still be a critical juncture with a foam roof
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Tell me a little more about taper insulation base. Does it require a tear off the existing structure, or the gravel? Will it make a significance energy difference?
The tear off is required if another layer will overload the structure. Otherwise, the tapered insulation can be installed over the existing roof. If there's gravel, it's likely BUR, so a membrane roof will have to be vented.
Yes, the gravel will have to be removed. If there's not an attic, there should be some energy savings, but that's a case by case situation.
There are two types of stock tapered boards. One type gains an inch per 4' and the other gains 2" per 4'. They are not cheap.http://grantlogan.net
Who got Bo Diddley's money?
OK, from what I can tell with my brother I guess I am driving the inspection truck (I feel like the road is very hazardous and weaving in the dark in a snow storm....).
What things should I be hearing about from a roofer to see if they have considered the current roof load?
I think there is a small attic area (the length of the building by 16" high, a guess, from looking at the depth of the access hatch in the second floor hall way). I know that there are issues with some sagging, so should I expect someone crawl into the attic space and up the 75' inside to the lowest dip location for an inspection?
Spray foam over lay is an interesting idea - still get the slope we would like to see.
I would assume that all deck repairs (ie find why / fix the current sagging) needs to be done prior to any spraying or foam overlay would take place.
Any one have a recommendation to get a quote / guess for either type (spray or sheet foams) from in the central Oh area?
"I would assume that all deck repairs (ie find why / fix the current sagging) needs to be done prior "I can't see it from here to evaluate, but most flat roof sagging is from one of two thingsA - the structure was overspanned originally and snow loads forced the sag in the rafter/joists.B - A small leak was left unattended for too long, and the moisture getting in damaged the lumber, weakening it and letting it sag.Either of those require a fix
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"taper insulation base. Does it require a tear off the existing structure, or the gravel? Will it make a significance energy difference? "Usually it would require a tear off. If there is a gravel surface, it can be easier to strip down to the sheathing than to just remove gravel. It all depends what is there now and what condition it is in.Any insulation adds to energy savings, but to really get much out of that, he would be adding another couple inches too besides the taper system. Problem there is leading to zero at the scuppers.
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