Roof repair help?

Hi…I just bought a new home and I know zero about roofing :confused:

The building inspection noted: “There is a modified bitumen roof, and several seams on the parapet walls are not properly welded together.” One pic is below, but others can be viewed here:

To note: Theses are all on a roughly 2.5’ high wall that goes around the perimeter of the roof…so these seams all run vertically.

Question 1: The roof is actually still under warranty from the previous owner…is this definitely an issue I should have them come fix? Obviously the gaps are small, but I also of course don’t want any rain getting into my home. I guess I just want to first confirm that these are a problem that needs to be fixed.

Question 2: Or…is this something I can easily fix myself? I understand these were originally heat-welded, but a friend mentioned “Henry” roof caulk that I could pump in the gaps…would that suffice? I do want to do things the right way, so if these should truly be heat-welded to fix properly, then I’d prefer to go that route and have the roofers come fix.

Thank you so much for your thoughts and advice-

To be more accurate, you appear to have a gravel surfaced Built Up Roof (BUR). The wall flashings which you have photos of are a granulated modified product, most likely an SBS product given the rest of the roof appears to be a BUR.

Yes, you have a problem. Actually you have more then one problem. Your flashings look like they were installed by a drunk monkey; or an unqualified, over confident do-it-yourselfer. They’re all disbonded from the substrate (not tightly installed to the wall). You’re missing a cant strip along the base flashing (this is the 45 degree angle change that keeps the flashings from prematurely cracking). I couldn’t see that any proper termination was installed- ie: metal coping cap or edge metal at the top of the parapet wall. And then there are the open laps… Here’s the thing about those laps: IF this is a heat welded product then it most likely has a poly burn film on the backside of the material, which means applying a flashing cement or caulking isn’t really going to do anything more then cover up your problems temporarily. The film backing won’t adhere to the cement. A qualified torch applicator should easily be able to fuse the laps together for you, but you’re still going to want to address the other problems.

You mentioned there might be some kind of warranty in place? You may want to look into that, I have a feeling you probably have nothing more then a generic product material warranty. This roof wouldn’t have passed the inspection to obtain a performance (labor and material NDL) warranty.

1 Like

Thanks so much for your help TJ. A few notes…

  • The building inspection also noted the lack of metal flashings on top of the parapet walls as well, but I did see the following language in the roofing company’s job proposal: “Cover parapet wall with mineral surfaced cap sheet set in hot asphalt and seal using a three-course flashing method.”
I know nothing about roofing, but the description above would seem to indicate that they employed this method of flashing instead of metal flashing. Am I reading that correctly? If this acceptable?
  • Regarding the cant strip: While I don’t really know what I’m looking at, it does appear that there’s a bit of a curve at the base of each wall. Possibly there is a cant strip under there?? If not, I’m not sure that they can exactly remove all the flashing and install this, so I’m making a guess that I’ll have to live with this.

  • Finally, I understand your note regarding the caulk not sticking to the poly burn film. Just to ask…if by chance the roofers won’t re-fuse my roof, instead of caulking “inside” the gap (i.e., where the poly burn film is), could I instead just put a long “band aid” of caulk on top of the outside of the gap to seal it? I know this isn’t the right way to do it, just asking the question though.

Thank you again for all your help-

If you have another photo of the top (horizontal surface) of the wall I can answer this a little more thoroughly. From what I see, the walls were indeed flashed with a mineral (granulated) cap sheet, but what we can’t tell is how the cap sheet was terminated at the top outside edge of the wall. It is not typical that the termination here would be to three course the cap to the edge of the wall. There should be some physical termination- usually some fashion of metal (cap, drip edge, etc.).

For the record, three coursing refers to applying a thin layer of flashing cement, embedding a layer of asphaltic impregnated reinforcement mesh and then applying another (for those counting along this would be the 3rd layer) layer of flashing cement over the reinforcement mesh. The last step in the process is to sprinkle loose granules over the exposed flashing cement to cover it up and give it some protection from the sun.

Back to the can’t strip real quick- if you can feel along the base of the wall and there is a solid 45 degree angle change (usually a 4" face where the transition is) then you have a cant installed and you’re good to go. If as you feel along the base its not solid, and is just ‘loosely’ installed (this is what it looks like to me in the photos) then you don’t have a cant strip, just poorly installed flashings that will probably prematurely crack / split over time. Worth noting, the cracking and splitting is going to happen faster if you live somewhere that experiences wide seasonal temperature changes- the Midwest and Norteast especially.

Ok, to answer your question about the the open laps. If you can’t get a qualified roofer to torch them closed you can install a ‘band aid’, and the best method of applying a band aid would be to three course over those laps. Ideally, you will center the flashing cement and reinforcing mesh so that it extends 3" onto either side of the open lap, so 6" wide band aid would be what the doctor would order.

In fair disclosure, I work for a roofing manufacturer who manufactures and sells these types of products. I don’t know if you’re planning to attempt these repairs yourself of if you have a contractor you are working with currently, but I would highly recommend you get in contact with a contractor who specializes in Commercial Low Slope Roofing, not one who does residential or shingle type projects. An easy place to go to is select “find a contractor” click on the tab for ‘commercial’, not residential, and enter your zip code for a list of contractors. Get a bid from a Master Select certified contractor. Other manufacturers for these types of products: GAF, Firestone Building Products, Johns Manville. - these are the ‘Commercial Manufacturers’ who have good Commercial contractors bases. I’d be careful going with any other brands (Tamko, MuleHide, Certanteed, Tri-Built, etc) or contractors who recommend other brands, they’re probably residential oriented contractors…

How large is your roof? A new roof may be worth looking at too if it’s a smaller roof…

TJ, didn’t forget about you…weather was simply bad here so I never made it back up to the roof to confirm the cant strip or get a better picture of the flashing.

In the end, the roofers are coming out next week to re-seal those vertical seams, so hopefully that will remedy things. They happened to mention those weren’t heat-sealed…rather they were “set in hot asphalt.” (I can’t really comment what’s bad or good since I wasn’t the one who hired them – the previous owners did – so regardless of how they originally did the work, I guess I should be glad they’re coming out to fix it under the warranty.)

We’ll see how it goes and I’ll take some pics when they’re up there.

Thank you again