Flat Roof Maintenance & Repair

Building I bought has a flat roof. It seems in good shape so far. It was replaced in 1994. I would like to keep it in good shape, since it would have to be really expensive to replace it, and I'm about broke after buying the building. It looks like most of it is kinda like roll roofing and is glued down-



The part of roof shown above is nice, as it is slopped so the water runs to the drains pretty good. As you can see, hardly any water sitting. However on the other wings of the building, the water is sitting, and it won't run to the drains. I kind of think that isn't good...it a inch or two deep in parts...how would I go about fixing that?

Also, any other advice on how to prolong the life of the roof would be really appreciated...how many years would a roof like this last? I'm not sure, but I think it had the original roof on it when the building was built (1950 & 1956), till it was replaced in '94.

Thanks!
Eric

Whats under it ?

The part with the standing water should get immediate attention.
You have to fix the slope.
The building I'm in has an old roof with that was covered with a new steel truss and sheet metal system. I know thats not what you want to do now but that might be a future solution for you.
SM

Its supposed to have a gypsum roof deck, with insulation under the roofing...changing the slope does sound like the way to go, but a pretty big project...probabley would mean tearing off the roll roofing, and adding material to the low spots...ouch!

Thanks!
Eric

If you can get up there, check your rafters and purlins see if any sag at the low spots, if so sister them to get the proper slope back, much easier than doing the roof.

Also, if you can get there, and the rafters etc are fine, see about installing new drains in the low spots. simple and very cheap if you do the work yourself.



Ken.

Flat roofs leak.
Always.

I have a rental where we just added a new, sloping roof right over the top of the existing flat roof. Extended the vent pipes, and put on cheapo metal roofing, where nobody would see it anyway.
Now it doesnt leak, and it wont.

I would agree, fix the drains, check for sag, but long term, add slope. Even a little bit makes a huge difference.

a way you can look after it is to paint it silver aluminium paint

that's what they are doing here in the UK ..

its reflects the light .

so also the ultra Violet rays that degrade it

stops the tar/bitumen drying out ...

once every five years should be enough .

all the best.markj

It looks like what you have is a modified bitumen single ply roof. If the courses of roofing measure about 36" then that's what it is. It was torched down over your insulation and a fiberglass base sheet. If you have good slope you should get about 20 years out of the roof.

You can do regular maintenace by getting a couple 5 gallon cans of modified roofing cement from your local roofing supply warehouse, and going around patching any cracks or splits you see. At some point you will probably want to begin coating the roof like Mark mentioned above...but for now just check it once or twice a year and do a little regular maintenace and it should be fine.

RE: the low spots...if they are really bad, mark the perimeters of the puddles with a construction crayon after a heavy rain. You (or your roofer) can glue down some tapered insullation right over your existing roof...and then add another layer of single ply roofing right over the top. Make sure you embed the new roll roofing in a heavy coat of roof cement, then roof cement and band felt the edges for the final seal. This will cure your low spots.

The roof in the picture lok spretty good. I wouldn't sweat it too much. With some simple regular maintenance you should be able to get many more years of service from your roof. I have about 30 years of extensive roofing experience...lots of flat work too.

Good luck!!

Eric ,
I regret every dollar I spent trying to maintain a flat roof . Hot tar , fibred roof cement , silver paint , filling in low spots , it just never ends .
If you have any sawmills in the area , start doing work for them in exchange for rough sawn 2X6's and 2X4's . As others have said , you can build simple trusses on top of the existing roof , and just build them in place . Once you have a gable end framed in on both ends , just run strings and fill in the blanks. trusses every 5 feet , 2x4 purlins every 24" and pole shed tin over the top .
Not what you want to hear , bu I did my 6000sq ft over a span of 15 years , and I now I don't have to wear bread bags over my socks to keep my feet dry !

i can't tell for sure, but it maybe a product known as "torchdown"

if it is and has been installed correctly it will last a very long time, not leak and can hold standing water without issues.

the stuff is fantastic!

if you see no sign of roofing nails tarred over, it is probably torch down.

if it is torchdown, do not under any circumstances put a nail in it, and never use
any form of roofing tar or cement, as it will soften and eat the stuff up.

they make a special tar like stuff, might be some form of acrylic i dunno.

have a roofing guy check it out to see what it is,,
torchdown looks alot like rollroofing

it can be plain or with any number of colors of sand surface as well.
comes in the standard 36" rolls as well. they also sell the sand to melt into the seams
during installation so it all looks nice and even.

find out what it is, and then decide what to do
would be my recommendation, you sure don't want to apply some tar and do more damage
to an otherwise good roof.

edit:
btw,, i read that it appears the roofing is glued down?
torchdown is heated on the back side with a weed burner, and as it melts it is rolled down.
this bonds it to the fibermat that is nailed down to the wood base.
and the result is a firmly bonded leak proof roof, if done properly

bob g

Thanks for the input! Much appreciated!

Yes, the strips of roofing are about 3 feet in width..interesting that it might be torchdown...and that you have to be careful what's applied to it...I know it came with a 10 year warranty for it to be "leak proof" from the company that did it...so far the roof seems great, I only have one tiny leak that I have found, just a couple drops running down a wall...

Thanks again!
Eric

When i applied the silver roof coating to my den roof it took about 15 minutes of mixing to bring ther silver up and throughly mix it in. So when I had to buy one gallon extra I had them shake it up. That helped a lot.
Bill D.

My house roof has just a slight slope, and it was originally covered with roll roofing (what they call "double coverage" or "half-lap" around here - Piedmont area of North Carolina).

I did the aluminum coating thing every five years or so and got over twenty years from the roofing before it became clear that something more was required.

I replaced it with white EPDM, which is like an extremely tough rubber that's .060 thick, comes in rolls about six feet wide, and is glued down to special 4 x 8 backer boards.

No problems after three years, my fingers are crossed.

John Madarasz said:

RE: the low spots...if they are really bad, mark the perimeters of the puddles with a construction crayon after a heavy rain.

Click to expand...

Another option, if you have only a few large puddle areas:

Mark the low point and mark that with a crayon under the water. Mark it well enough that it won't come off with the water sitting on it.

When the water dries up, put a drain there.

Steve

I would recommend you applying EPDM Liquid Rubber to the Roof. When applied properly EPDM Liquid Rubber creates a seamless membrane which will fill up any cracks and tears on the roof and stands up extremely well to ponding. With EPDM Liquid Rubber you can get a new roof at fraction of the cost of roof replacement. A coat of high quality EPDM Liquid Rubber can restore an existing roof to like-new condition. It may delay the need for roof replacement by adding up to 18 to 20 years of guaranteed life protection to your existing roof.

lillianquinteroe said:

I would recommend you applying EPDM Liquid Rubber to the Roof. When applied properly EPDM Liquid Rubber creates a seamless membrane which will fill up any cracks and tears on the roof and stands up extremely well to ponding. With EPDM Liquid Rubber you can get a new roof at fraction of the cost of roof replacement. A coat of high quality EPDM Liquid Rubber can restore an existing roof to like-new condition. It may delay the need for roof replacement by adding up to 18 to 20 years of guaranteed life protection to your existing roof.

Click to expand...

Now let's take a look see...WHy would you dreg up a post from 2008 to offer this "sage advice" ????

Gee....I wonder why (look at spammers "about me" listing)