Rubber Roof

We seldom see these roofs here .Building is 40 ft * 80 ft. Roof is about 60% covered with water .No leaks and is 6 years old .
.What if any concerns are there.
Does the water shorten the expected life of a membrain roof.
How can this be fixed???




Poor planning for design/placement of roof drainage system.

Water sitting on a roof is a problem waiting to happen. Water ponding for short periods of time is fairly common (up to 48 hours) on flat roofs unless there is a roof design incorporated to drain the water properly.

I have a flat tar and gravel roof system on my house, and considering replacing it with rubber. Even with the best of design and installations ponding does happen in places that ponding was never planned. I have photographed and noted them to build up one specific area that seems to have been caused by some settlement in the structure at a large 8 x 8 skylight area. Other than that the old T&G roof has served us well for over 25 years.

Roy the Phone Company have been using that type of roof for many years . Water is a issue and should be corrected, Another problem we had were birds yes believe it or not during Shad fly season they would pick the hell out of it lolol getting the bugs.

No roof should be “flat”. All roof should drain. Ponding water is a problem.

Exactly…a 20’ x 20’ x 1" deep puddle of water weighs about 1 ton. Maybe they can install some drains/scuppers where needed.

Thanks Claude,Wayne, Joe and Larry very much appreciated … Roy

Hello all, first time posting. I am not a building inspector, but I do enjoy reading your forums. I specialize in roofing (mostly flat), and am a Registered Roof Observer.

Usually any ponding that dissapears after 48 hours is not a concern.

EPDM roofs have a couple issues to watch out for… they shrink and tend to pull away from perimeters or projections, so the old flashing has to be cut, and new flashing patched in. The seams should be monitored as they will be the first thing to start leaking. Caulking at the perimeter will also weather and leak over time.

Ponding can be remedied by adding another drain as others mentioned, or when it comes time to re-roof by adding tapered insulation.

Thank Lee This was a concern to me as this water was from many days ago.
I could not get onto the roof as the ladder was too short.

The main reason for any shrinkage is the insulation underlayment. The membrane seated atop the insulation gets pulled of the can strip, angle changes, as explain by LEE penetrations although they can be repaired for the exterior, ETC.

I have one photo you sent me Roy that shows the membrane has shifted.

No big issue I suspect. Very small area at the flashing. No parapet wall to speak of so it must be 4 or 5" can strip.

EPDM is a big rubber membrane. It can expand and retract to its original form.

All good. I forgot abut the 2 day rule over the phone Roy. Thanks Lee.

Blue insulation and BUR or any membrane where banned in Quebec in 1980. I worked the next year in Calgary. I told my supervisor to get the brush off.

It was a mainstay of roofs back in the day. I was installing blue in 1978.

Now they must install tentest on top and insulation that is more heat resistant to shrinkage.


The tentest stays inplace even if the insulation does shrink a little.

“Now the main plumbing stacks are a concern for me.” I only reviewed the photos for 5 minutes . No zoom buddy. Sorry.

They should have an aluminum or galvanized flashing “flange” with a special breather hat.

The ABC 90% plumbing connection links are a cheap trick, if those are main vent stacks. "Not a good idea what so every " IMO.

#1 Shear loading the vent stack piping can empty the P trps for one Roy.

#2 cold air can assert a host of issues.

#3 cross contamination. Air = small or odour coming out of an empty trap…

See if they are main stack vents.

Roofers save money by not installing aluminum flanges and hats.


Call your friend tomorrow and ask him are those main vent stacks…

The system are great.

I will note; If the plumbing stake venting .

I would recommend the ABC 90 come off if they are.

“Water pools on the flat roof. While we refer to this type of roof as “flat”, it should actually be designed with a slight slope so that the water runs off without pooling, which can lead to leaks. We recommend that a competent roofing contractor evaluate the roof prior to the close of escrow or within the contingency period.”

Fare statement Joe.

Building settlement is the number one cause of pooling.

I agree with your assessment that a roofer evaluate and report condition.
If the roof is under warranty then the installer (roofer) can verify condition allowing a transferable warranty.
That should please all concerned if the building is on the market.

A lewinsky you say.
I do not know whom to believe? You or the client.:wink: HA HA HA HA.

Says who? Please post links to your accredited sources that confirm this.

Claude do not change your roof into another systems as of yet. Bur roofing is still the best dollar value.
Not to many know about BUR roofing other than it is tar and felt.
It is complex system and when enacted properly is and excellent membrane.
Roofing with tar and gravel…read more.

I have started collecting data on the new systems being introduced into our province.
BUR roofing is to me the most stable of roofing systems even on sloped roofing. 25 to 40 years with maintenance.
Sloped roofing and BUR systems are not practiced as a system of choice nowadays but back in the day I use to flash parapet sidewalls and protrusions, boxed openings for the goose neck flashing, with type 3 tar. We had 3 kettles and one tanker on the job at times.
Flat decks used type #1
Any slope lower the 2/12 used #2 and the progression went on like that.
We used mechanical applicators for most everything except where the machinery would not fit or another crew was not working they company would slow down the job using men mopping and graveling. .

If the system was applied properly, 4-5-6 ply with all stripping and adequate flashing intact the 25 years is a minimum and 40 years not unheard of.

EPDM is industrial/commercial application with a short life as compared to pitch roof or BUR roofing.

Everything settles Jeffrey?
Nothing stays ridged unless you take viagra…:wink:
If you asked nicely the link may improve.

All the best.

I see gravel stops but no scuppers so should have a gutter at the back end and yes needs to slope .
As mentioned should have dissipated within 48 hours so pounding needs to be corrected.
However I found this interesting…

Unlike most asphalt base products that are limited in their installation to a fully adhered application and have restrictions of ponded water, EPDM membrane can be used successfully in exposed or concealed assemblies due to its ability to withstand temperature extremes and resist the absorption of moisture.


Ponded water on an EPDM roofing system will not void a manufacturer’s warranty or be the sole reason to deny issuance of a warranty. During the design phase, however, efforts should be made to incorporate positive drainage into the roofing assembly to avoid excessive ponding. It is beneficial to avoid ponding water due to the expense associated with its removal in the event of repairs and also to reduce moisture infiltration and damage in the event of incidental puncture.


In addition to the number and size of roof drains, drains should be positioned in low areas to eliminate ponded areas. Also, crickets and saddles may be incorporated to divert water and reduce the accumulation of water. If necessary, tapered insulation may be incorporated throughout the roof or in localized areas where additional drainage is needed.

Hmmm… Don’t say nuthing about…

Try again, Robert!

Nice material Bob. first class mate.:slight_smile: Bobs your uncle.:wink: with material like that.
#1 Buildup roofing slope to the drain is one answer.
The insulation is engineered for that roof and drainage system layout.The roof is pitch to the drain by means of the insulation layout. It will be 4" higher and taper to zero at the drain.

#2 You have to take the parameter into account.
Parapet wall is built up out of lumber and metal flashing is all changed out.
It does cost money.

As you explained. EPDM is theoretically bullet proof except for; #a Seam adhesion, they are glued in place. #b penetrations from fastener lift or pressure point entry. Walk on a sharp object left on the roof.

The ponding is OK but; a open penetration or punctured- seam lets go, in the low spot of standing water it is a swimming pool being emptied and no way to stop it.

Thanks Bob.
Hope you enjoy tomorrow with friends and family.

R. Young. You’re posts are painful to read. First because they are full of a bunch of information no one really asked for. And second because the info. isn’t really accurate. That wiki link says nothing about foundation settlement being number one cause of ponding on flat rubber roofs. Also I was just looking in the Canada page where someone posted an electrical panel where there was no ground lug or terminal strip for the grounds. Hence they were all wrapped together and improperly (grounded) wrapped around the screws for the panel cover. It litterally slapped you in the face and you ignored it and then went on to comment how the plumbing was wrong - which was also incorrect, the plumbing was fine! What gives? Get it together Canada.

juston you do not have to read the pain full material now do you?
I did not even look at the electrical. Read my posts. HA HA HA HA

If it was so obvious then why did other say good catch? Yes a slap in you face.

So If you are so knowledgeable** prove me wrong**:wink:

All the best
See you just joined INACHI.
Get ready for another opinionated SOB.

One last post for a while.
Prove me wrong Jeffrey.:wink:

Man what a total waste of space.