Flat Roof work -- should we coat or re-layer?

Hi everyone,

Just discovered this forum and reading through the posts – what a great resource for people who need advice. Hoping i can ask a question or two as i try to educate myself on roof work.

Roof Details:
We have a 14 unit condo, 5 stories tall, with a flat (Bitumen?) roof. It was built in the 1920s. Surface area maybe 50ft x 150ft (very rough estimate). We are in Illinois.

Current State of Roof:
It’s clear that there has been some minor leaking in various places for years. Over the past year ive gone up and put buckets under the leaks/drips. There are lots of little dripping leaks in different places, but nothing really major, and doesn’t seem like any real structural damage anywhere. Most of the leaks seem to occur near brickwork areas (chimney etc.).

Contractor Quotes:

We’ve solicited quotes to have roof work done, the contractors seem to think the roof is in quite good structural shape, no real give as you walk on it; plenty of “alligatoring” though.

When we got back quotes, we realized that the 2 contractors have proposed very different things.

One proposed:
Fasten one inch polyisocyanurate roof insulation over the bitumen membrane, then install 0.06 EPDM membrane roof system, and flash walls, and various other details. The quote was about $27,000

The other proposed:
Reinforce 200LF of seams on roof 6" Tietex reinforcement fabric and Lucas aluminum plastic cement, and then install a coating of Lucas thermo-metallic elastomeric Aluminum roof coating. They gave us a few additional options regarding whether to put a second layer of coating on. They will also do a few more things to improve gutter, etc. The quote was about $8,000

Advice Needed:

What i’d really love to hear is some opinion about the different options.

My initial uninformed thoughts:

The building isn’t really flush with money, so the $8,000 is quite appealing. And because the roof seems in fairly good shape it seems reasonable?

On the other hand… I don’t know if that’s just wasting money on a temporary short term fix. (We are up 5 stories, and in this area that means a bit of expense and work to get stuff craned up to the roof, so short-term solutions are even less appealing).

So… please tell me what you think? Or how you think we should be weighing these options or others? I know you can’t give definitive recommendations but i’d really appreciate any advice you could give on how we should be thinking about the choices…

Thanks in advance,
s.r.

s.r., you got to get somebody to do a test cut in a few different areas. get a independant guy like a roof consultant. you dont know whats under that roof since 1920 or what the deck is? did you own the bldg. when the last roof was installed? if so did they remove the old or go over it?

corry,

thanks for the quick reply. have no idea about history of the roof, and neither does anyone else, and the records are almost non-existent.

the contractor that proposed the $27K re-layering job actually did cut out a little squar section of the roof but didn’t say anything about what he found. Both contractors did say that the deck seemed sound and pointed out the alligatoring.

what would we be looking for to help determine how to move forward? what are you curious about that could help sway us in one way or another?

-sr

EDIT:
someone else in the building thinks that the roof was replaced (or relayered?) about 20 years ago.

I should add that half of the roof has a nice good slope, and has basically no leaks… then there is a flatter part where the leaks are… going up after a rain shows only a couple very small areas with pretty minimal ponding. contractors came up after rain and said it basically looked pretty good.

coating seams is putting a bandaid on a cancer patient. put a roof on the whole bldg. 20 yrs is a long lifespan for either modified bitumen or bur.
i would also get at least 6 estimates.
where are you located?

I would think a 1920’s building is going to have either a wood, gypsum or possibly a masonry deck, so I’d would check first to see what kind of deck you have from underneath the roof.

Next, if you have saturated plies, covering the wet roof with EPDM or a coating really isn’t the answer. However, if you feel the need to leave the existing roof in place, look into HydroStop.

We’re in champaign-urbana. There is an attic under the roof so you can see that the deck seems made out of wood. From the attic the roof looks in fine shape except for the leaks that drip during heavy rains.

1920 bldg. hmmmmm. a roof poss. every 20 yrs.,=4,or 5 layers. I would say you may want of find that out before you roll out another 1 over the top…
I know a guy that drives a 3-1/2 in. nail into the roof to check thickness,before he will suggest any solutions,lol

srj, how big a roof is it? $27,000 seems high for a go-over.

just a guess, it’s probably somewhere around 5000-7500 sq ft.

srj,that price if its 50-75 sqs. ranges from $550 per sq. which seems low to me @ that height, to $3,600 per sq. which seems too high. your just going to have to get some test cuts done to figure out the layers & then decide from there if it needs a tear off or if you can go over.

from contractor with the $27k quote to re-layer roof, he cut into roof to see what was there, says:

3-4 ply asphalt+felt, with modified bitumen on top; about 1" thick.

i assume that means the roof of this 1929 building was torn off and replaced a couple of times.

the building is leaning towards trying the cheaper quote for coating, which includes some non-trivial re-reflashing work in the price, to see if we can get another 5-8 years out of the roof.

does that seem reasonable? or is it just throwing away money and we should go for the re-layering?

[quote=“sreja”]from contractor with the $27k quote to re-layer roof, he cut into roof to see what was there, says:

3-4 ply asphalt+felt, with modified bitumen on top; about 1" thick.

i assume that means the roof of this 1929 building was torn off and replaced a couple of times.

the building is leaning towards trying the cheaper quote for coating, which includes some non-trivial re-reflashing work in the price, to see if we can get another 5-8 years out of the roof.

does that seem reasonable? or is it just throwing away money and we should go for the re-layering?[/quote]

Without seeing the roof for myself, I would say you should probably tear it off and replace it; however, short of doing that you can coat the roof, but make sure it is a coating that provides a 5- 10- 15- and/or 20-year warranties. There are a few good coatings out there, and an awful lot of bad ones. Choose wisely, or you will be sorry in the long-term.

srj; im w/ cerberus. if your going to recoat, use a good product like tremco or koppers. so youll get a warranty. dont use something cheap from home depot or lowes.

The one quote was to put on Lucas #3000 – what do you think about using that?

Info here:
rmlucas.com/ALUMINUMCOATINGS.htm

Or brochure in pdf, converted to html by google cache here:

74.125.95.132/search?q=cache:_xH … clnk&gl=us

Just took some photos of the roof, maybe that will help?

this is the edge where the entire roof flows off (everything slopes to here):
http://mouser.dcmembers.com/roof/001.jpg

one area where flat room meets shingled roof:
http://mouser.dcmembers.com/roof/002.jpg

sample aligatoring:
http://mouser.dcmembers.com/roof/003.jpg

one border wall with giant nails showing:
http://mouser.dcmembers.com/roof/004.jpg

metal border at high point of roof (North):
http://mouser.dcmembers.com/roof/005.jpg

the leaks are almost all where roof meets masonry, it looks like there have already been some patches over the years:
http://mouser.dcmembers.com/roof/006.jpg
http://mouser.dcmembers.com/roof/007.jpg

more aligatoring:
http://mouser.dcmembers.com/roof/008.jpg

inbetween chimney masonry and elevatorshaft-roof entrance room (there is a leak below here):
http://mouser.dcmembers.com/roof/009.jpg

more evidence of prior repair:
http://mouser.dcmembers.com/roof/010.jpg

worst of the alligatoring:
http://mouser.dcmembers.com/roof/011.jpg

That is beyond coating…salt on an open wound,sorry but it looks like a re-roof is in order…

Also if it were me I would be looking into a full tear off,to see how much damage the leaking has caused.It will not just dry up on its own,it will just fester and in the near future you will have a HUGE PROBLEM and be out ALLOT more$$$$$$$$$ Do it now and SAVE BIG $$$$$$!!! And who ever you consider to use for the job,Check the refs…look at older jobs,and speak to the customer…

srj, i agree w/ jwolf. you should replace & also all the thru-wall or wall cut counter flashings have been removed by a previous roofer! when you get the roof done have them find the location of the weep holes in the masonry walls, & be sure they dont roof any higher up than them weep holes. then have them install wall cut counter flashing. because term bar by itself, like it is now, is no good. its a proven fact. also be sure to discuss this w/ the estimator/ roof salesman. you probably could repair & coat but yould be throwing away your money by just putting a bandaid on it. get them counter flashings installed.

Thank you all for the comments and advice – really can’t tell you how much it helps.

Regarding the tear-off vs putting a new layer on top… It seems like a tear-off would be hugely expensive, especially given that we are 5 stories up.

From the attic looking up the roof, it seems pretty good and solid with not much sign of water damage. there are quite a few leaks that drip during heavy rains but nothing catastrophic. and from walking on what feels like a pretty solid roof.

Do you all still feel like the existing roof has to be ripped off and that putting another layer of insulation and roof on top would be ill-advised?

If we have a $27k quote for putting a new layer on top, i shudder to think about the costs of tearing off the current roof and putting on a new one.

Thank you all so much for spending your time helping me figure this out.