Flat Roof Questions, Advice, Ballpark Estimate — RoofingSiding — DIY Home Improvement DIYChatroom

Flat Roof Questions, Advice, Ballpark Estimate - RoofingSiding - DIY Home Improvement DIYChatroom

Flat roof questions, advice, ballpark estimate


I’m seeking advice about replacing my flat roof. I have some water discoloration on the ceiling of my top floor in a couple of areas. I noticed it late last fall a few days after some particularly heavy and windy rains, and then it started to get cold, so I didn’t figure I’d be able to get it fixed reasonably before the winter. Hopefully there hasn’t been too much additional damage.

I’m in Chicago (city), in a row of 6 connected townhomes with 2 adjacent neighbors. The roof is continuous across all 6 units, but my section is just adjacent to my 2 adjoining neighbor’s roofs, so I’m not sure if this presents any special problems/considerations. Getting everyone to replace the entire 6 unit’s roofs or even mine and my 2 neighbor’s roof area would be out of the question. The townhome is 18 years old, so I think I’m due for a new roof anyway. The existing roof is either rubber or bitumen I think.

Unfortunately there is also a rooftop deck built on top of the roof which would have to be torn down. Access to the roof is through a roof hatch. The patch of roof covering my unit is no more than 1000 square feet. There are several metal (zinc I think) tube chimneys and vents and the AC unit is on top of the roof as well. In other words, a few obstacles to deal with, but not much surface area. I plan to remove the rooftop deck and leave it removed for at least a year to make sure the replacement roof is sound and leak-free before I even think about replacing the deck; I never use it anyway.

I have this bad feeling this is going to be very expensive to replace, and I have concerns about how I will be able to trust that whomever I have do this job can demonstrate to my satisfaction that the leaks have been found and stopped. I’m also not clear on whether I should strip and replace or just resurface over what is there (I’m guessing the former from what I’ve read here so far). So on to my questions.

1) Would anyone want to hazard a ballpark guess as to what this might cost? Are we talking $5K, $10K, $15K, or $20K or higher for what I’ve described and where I live? I have no idea what to expect, and I don’t want to be ripped off nor do I want to go cheap with shoddy workmanship.

2) Should I remove and replace the entire surface or just put new over the top of the old stuff? If I remove and replace, how does one deal with the continuous nature of the roof with my adjoining neighbor’s units?

3) Do I need someone specially licenced and insured to deal with this neighbor situation so that if their roof starts to leak after mine is replaced, I’m protected from liability? What specific kinds of extra insurance or legal documentation should I look for and require to deal with this situation? I.E. I think I need something in writing that pretty clearly states that if my neighbor’s roof starts leaking within X amount of time after my replacement, that my roofer will be held responsible for paying to inspect and prove that it isn’t their work that caused it. I’m just not sure what this document would be or if it’s part of a standard contract or what.

4) To determine the source of the leak or extent of the interior damage, who does that and how does one go about doing that? Is there some sort of detector that works through walls, etc. that can trace moisture or does this require a visual inspection? Will a borescope and a few small holes here and there work for this type of thing? I’ve been considering getting one of these myself anyway for my own peace of mind. Or does the interior ceiling and insulation, etc. have to be torn out and replaced entirely? Does the roofer have this kind of equipment or is that another contractor’s job, and who does that interior work? Does the roofer usually subcontract that or do I need to do that?

5) Who or how does one check for mold, wood rot, etc. Does my roofer do that, or do I need another contractor for that type of thing or does the roofer subcontract that? How is the mold and/or rot detected? Some type of meter/detector, or is this visual inspection also?

Flat Roof Questions, Advice, Ballpark Estimate - RoofingSiding - DIY Home Improvement DIYChatroom

As you can tell one of my biggest concerns is how it can be demonstrated to me that the leak is fixed afterward, and that I have no mold, rot, etc. remaining.

6) Is it normal / expected for a roofer to come back, say a year later to inspect and verify there are still no leaks? Is this normally included in the cost or is this extra, and if extra, how much should this cost? Or do I have to wait for a leak to re-appear before I know a year later that everything is still OK. My point here is that before I put back on the roof deck, I want to make sure there is no further leaking, even if there is not yet any visible damage on my interior ceiling for example.

7) How is the roof protected from leaks if it rains/storms while the work is in progress? Is there a period of time where I’m at risk if a storm/rain hits while the work is in progress? Or is everything sealed up after each day’s work? Also, how long should a job like this take?

8) Is there any alternative to a roof deck structure? I.E. is there some kind of embedded heavy duty roofing material I could have put over a patch of the roof that is durable enough for the same type of recreation that one would do on a normal wooden rooftop deck? I hate the idea that if in 3 years I have a problem, I have to pay to tear down the deck to get at the roof to repair it. Or almost worse, if the act of building the deck tears up the roof somehow and I’ll know it just after it’s built only to have to tear it down again. If there was something that was more easily removed or just part of the roof itself that behaved like a deck, but really wasn’t an actual built-up deck, that would be ideal. I think I need the deck for the resale value of the house, but I can’t stand the idea of possibly having to tear it out someday again. I’ve also considered possibly getting thin-film solar instead given the future energy prices I foresee, which would be relatively lightweight even with frames. The roof already holds the existing deck and the AC compressor, so I figure instead of a deck, perhaps it might hold solar panels. My point is that I think I need *something* up there for the resale value of the house other than just a bare roof, but whatever I put up there, I want to make sure installing it doesn’t cause a leak or make it incredibly difficult to do maintenance on the roof.

Thanks in advance to anyone willing to help answer some/all of my questions.

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