Need advice on repairing flat roof leaks

We have a flat rubber roof on a 100+ year old house, with estimates that the roof is probably 10 years old (but it could be older - we’ve only owned the house for 4 years). We’ve had leaks since we bought the house, first related to skylights which we had replaced. Over the past two years, we’ve had cement patches done each winter to fix leaks into the bedroom at the back of the house. We got some estimates for more extensive repairs, but the companies we talked to said that they don’t repair rubber roofs and would only replace them. So we did the patching and hoped for the best.

During a recent rain storm, we had new leaking (near the skylights), so we’ve gotten a few new estimates. All three companies we’ve talked to this time say that we don’t need a whole new roof. But each has suggested a different way of repairing the roof. One said that we need to re-do the flashing around the skylights and vents in the roof by reapplying bitumen rubber to those areas. Another has said that they can use cement to repair the flashing, and then they will coat the roof with aluminum paint. The third said that they would use bitumen rubber and cement to repair the flashing (they said that the bitumen won’t fit in some areas because of how the skylights were installed) and then would paint the whole roof with aluminum paint.

If anyone can help us figure out which of these suggestions makes the most sense, we would appreciate it! Alternatively, does it make sense to repair a flat rubber roof, or should it really just be replaced?

Thank you in advance for your help!

give me a call to discuss 631-724-9511 Jeff

first off ,
bitumen and rubber ,to me, are two different things.
if you have a bitumen torchdown roof you may be able to save it.
if you have a rubber roof (like in black innertube rubber), then you mite want to reroof. im not to kind to rubber or plastic on the roof.

i mite get elled at for that remark.


if you can take some pictures and post theme we can solve your problem other wise it is really just a guess.
like he said rubber and bitumen are to different things that do not get used together
if it is a rubber roof with the flashing improperly installed then the correct way to fix it is to clean and prime the roof before installing new rubber flashing.
if it is a built up roof they need to install a layer of organic base (baker flashing) then install modified cap sheet over that for there flashing .
but it is all just a guess with out some pictures .

you can probably be you own judge.
if the roof has standing water, had repair after repair ie caulk,tar patches, or just to you untrained eye “looks bad” then tear it all off add pitch and start over.
if it looks good and just needs some love also known as tar. than do the repairs and silver coat.

if replacement is not an option and its shot spend as little as possible. just chase the leaks with the guy that seems most reliable. you will be calling often.
silver coat is fluff. it reflects uv rays keeps the roof cooler but if there is standing water it comes off. it also does nothing for leaks. silver coat is best applied to newer roofs to extend their lives. once the roof is gone it doesn’t do squat.

to ngmargie:

Hi. This one is LONG, but i recommend you read it :slight_smile: … It will save you a few bucks here and there …

Well, first of all, think how much money you spent fixing it in the last 4 years. add the repairs to the inside. From what you’ve described about the proposed fixes, it will cost you anywhere from 700 to maybe a few thousands to fix it ( I mean the aluminum paint options) Also add the additional cost to run AC when your roof gets to like 170 degrees.

Now, the aluminum pain … i just love this one. There are coatings which are not cheap ( and if you prefer cheap stuff, don’t forget that you’ll pay for it twice) I’ve never heard of a coating containing aluminum, and i just don’t see how alum powder would help it. but enough about alum. You CAN NOT coat that roof, because it tis loose… moisture under the roof expands, thus the roof moves. If you coat it, the coating will soon crack. So all in all painting is out of the question.

Now i’m still not sure what you have on your roof, but either way you must understand a simple fact - no matter how many patches you do, it will leak… again and again and again. So stop wasting your money.
No matter how much it hurts to put on a new roof i recommend it, as the only practical solution, unless you are willing to accept the leaks… but in the end it will cost you more… so do it now.
As for the sky-light, it might not be the flashing. sometime there is not enough pitch and a sky-light needs a curb… or the sky-light it-self leaks… I’ve seen those.

So, if you DO decide to replace it:
Forget about the contractors that you’ve mentioned above… the can only sell you another one of those junk flat roofs like tat+gravel or modified or epdm… they all will leak ( good example is your current roof ). Find a company that installs single-ply membranes. Preferably CPA (IB roof).

Our main specialty is Flat and Metal roofs, and on ALL of our flat roofs we use IB roof. I consider it to be the best on the market. It has a lifetime residential warranty. It is energy efficient cool roof. To be short, it is just GREAT product, and I won’t use anything else.
Go to their website - , call 800 number and get in touch with the local rep. in your area. He will recommend you people that are certified by IB and usually know what they are doing.

you can also see our web-site - , there is a great section describing IB roof in more details, but very easy to read and helpful.

Good luck.

PS, do not settle for a slightly cheaper TPO or EPDM… they are junk, especially the epdm :slight_smile:

Leo, I don’t know what you’re talking about. You can put coatings on low slope Mod Bit roofs and EPDM is a proven product in both commercial and residential applications.

Like someone above said, if a full replace is not needed or not an option at this time then have repairs done with tar and fabric then coat the roof with goop of choice (there are several). It may buy you a few more years.


OK, well for one thing you don’t coat EPDM. For another, sometimes the customer doesn’t have the money to re-roof at the time and if you can tar and fabric/coat a modified roof and get them another 3yrs then they can afford to put a new roof on at that time. Don’t know where you get 1/3-1/2 the cost for repairing though, that’s crazy. We’re talking maybe a couple hundred or so dollars, compared to a couple thousand.

POlyurea will fix both of those types of roofs.

Why would someone suggest a privaate phone call to diuscuss? What is wrong with right here?

To Tar Monkey:

The goop i use works for the following: Masonry, BUR, Metal, Single-ply,
and epdm is single-ply, so you CAN coal it.
I really don’t know who’d fix a sky-light flashing and multiple leaks for $200… never mind coating it. and when you actually do those thing ( i don’t mickey-mousing the job with roof goop from home depot) you do actually spend 1/3-1/2. Where i get this numbers? Materials, prep’ing the roof (cleaning, removing old flashings) spending time on appraising the job, possible rental for a “goop sprayer” (unless you do those all day long, and not every roofer does) the cost of goop… etc.
consider that you are leaving the wet insulation or whatever there is under the membrane, which will slowly rot the roof deck… IMHO doing the job that way is just screwing the customer, who is not knowledgeable enough. that’s where I get the numbers… I don’t believe in "coming in with a pale of home depot crap and a big spoon, and spread it all over the place"
I’ve fixed too many of those roofs, and what customers tell me is something like: “over the last few years, I’ve spent more money patching this roof than you charge me for an new one” Add the cost of the original roof to that… gets quiet expensive :slight_smile:
In the end you get a costly repair that WILL leak in a matter of 6-12 months if not less, and NO WARRANTY…

Is it really worth it?

PS: ( I’ve Just installed and IB roof instead of a 18 months old epdm roof that had over 10 patch works and was still leaking… i just do not believe in "do you best and caulk the rest :slight_smile: )

If an 18 mo old EPDM roof was leaking then the installer was at fault, not the material. I’m really tired of arguing with people on this board so you get to win.

First off- you need to determine what type of roofing it actually is and how its installed, there are many different ways to install EPDM Rubber Roofing, as well
as Bitumen Roofing. Rubber, like tire inner tube.
Bitumen is like thicker rubber and sometimes has a slight sand paper like texture.(it can be smooth faced also)

Once you have that answered then you can determine your best course of action.

Rubber for example : flat roof over screen porch, can be
fully adhered to the roof decking, loose laid with batten straps holding the seams, etc.

check for seams, is the roofing one piece? how is the edge of the roofing finished, is there metal edging?

all of this will help you figure out what type roof you have.

Roof : skylights, pipes etc. are they flashed properly, are they installed properly?

skylights, are installed first, the rubber roofing is made to run the roof up to the skylight flange, Flashing Tape(for rubber system ) is then adhered down the skylight edge and over the roof rubber to form a proper flashing seal. then caulked at the seam edges with rubber sealer. check this, are there areas where the seams have pulled apart or gaps? this will allow leaks.

pipes, rubber will have rubber boot(pipe collar) this attaches to the rubber roof, flashing tape is applied here as well,and caulking, are there any issues here?

Does the roofing have excessive patches,if so in my opinion , it would be more cost-effective to have it redone. Me personally, I would not use roof coatings, to me they are a temporary fix, and could resort in you doing this again in few years.

Do the research, like here and try web sites for manufacture for information. Then decide, What types of costs are you willing to do to get the most benefits from. Your Home is your biggest asset, and
relaxation is the bigger reward.

wow now i understand flat roofing and its idiosyncracies.

In my personal opinion, if you have a flat roof and it leaks, replace it with a pitched roof. Repairing a flat roof is foolish and you end up with what you deserve, leaks. I have had customers with flat roofs contact me with problems and I send them elsewhere

" if you have a flat roof and it leaks, replace it with a pitched roof."

“Flat roof” is an expression. All roofs should have some pitch.

well finally, a skilled master tradesman.john have you ever “installed” a complete flat roof system or is your knoledge limited to a one gallon pail of plastic cement and a 99 cent plastic trowel?

I deck 2 roofs for a guy, that is all I did. he put the “GRACE” ice and water shield over the decking! Both leaked, but was nothing to do with the decking.
I know of several more store roofs in NH that leaked within days of being done. Some cases where blamed on tree limbs falling. One case, they blamed it on pidgons, many of these roofs had a pitch of 1 to 2 inches overall but no more. No matter how it is done, snow on a semi flat roof makes no sense to me. And I just will not do one. Here in NC, 3/12 pitch is about the least I have done and felt comfortable with admitting it was my job.

Here in N Mich we get plenty of snow…
We have plenty of flat roofs, they only leak when the roof is worn out or because of poor workmanship…
Flat roofs do require maintanence and they tend to get much more foot traffic…
When there is a leak on a newer roof it is usually because of poor workmanship…
Perhaps more “roofers” need to learn a bit more about flat roofs…
They are a different animal but still easy to tame…

[quote=“JOHN THE HANDYMAN”]I deck 2 roofs for a guy, that is all I did. he put the “GRACE” ice and water shield over the decking! Both leaked, but was nothing to do with the decking.
I know of several more store roofs in NH that leaked within days of being done. Some cases where blamed on tree limbs falling. One case, they blamed it on pidgons, many of these roofs had a pitch of 1 to 2 inches overall but no more. No matter how it is done, snow on a semi flat roof makes no sense to me. And I just will not do one. Here in NC, 3/12 pitch is about the least I have done and felt comfortable with admitting it was my job.[/quote]

John , NEVER use Grace on a low sloped “flat” roof because that is not what it is designed for , it is designed for being on steep roofs under the shingles so that any ice or water that backs up from the gutter or in the valleys cant get under the shingles and make a leak , hence the name "ice and water shield"
Just from what you said in your previous posts in this thread flat roofs are not your cup of tea.
I would suspect this is from lack of training and the improper use of residential materials on “flat” roofs.

FLat roofs need to withstand ponding water without leaking and that is something that residential products simply aren’t designed to do.If your commercial roofer is having these types of problems and then blames the leaks on pigeons i think it`s time to find a new commercial roofer , one who knows what types of products will work on a given surface and how to install those products