BUR roof repair

I am looking for advice on a 4 ply BUR repair. One of my plants in Miss. (lots of sun and rain) has developed a substantial leak near the gutter edge of the roof at the flashing. Prior to my involvement, repairs were attempted by mopping in additional plies of felt initially then just flood coating with bitumen which has since alligatored as you would expect. Long story short, the additional plies and flood coat have raised what is supposed to be the lowest point of the roof which has caused ponding about 6’ in from the edge. To remedy this I want to do a tear off of the first 6’ (the old repairs) to re-establish the propper slope but can I effectively tie this back in to the remaining good BUR because of the lapping? I can’t justify a complete tear off seeing as the majority of the roof is in good shape.


Yes you can; however, you will have a back-water lap where you tie-in to the existing roof. Still, if done properly it should not be a problem, but the tie-in may create a hump in the roof and cause water to pond up-slope from the new tie-in. There are ways to avoid this also, but I’d need to know if you have roof insulation or if the existing system is installed overtop of insulating lightweight concrete fill. Based on your comments, I assume the entire roof is surfaced with an asphalt flood coat and stone aggregate. And, it is asphalt and not coal-tar pitch, right?

The system is not ballasted with rock and only the first 6’ has been flood coated with asphalt in a failed attempt to repair. The remainder is in an as-installed state (approx 10-15 years in age). The roof was originally topcoated with a white or silver UV coating which I plan to rejuvinate after making this repair.

There is a ~3/4" fiber board or insulation board under the felt and on top of a precast concrete panel system. I would not be opposed to removing or reducing the 3/4" board in an attempt to correct the pitch problem. Can the repair be ‘under lapped’ under the original roof to avoid the hump you mention?

Another related question - this roof section is 200’ in width however only 75’ has guttering. The rest has a raised lip similar to a gravel stop to restrict water from cascading over the edge. I’ve never seen this done. Wouldn’t it be better to have the entire length guttered rather than trying to divert the water to the middle guttered section? There is no tapered insulation system to force the direction of flow.

Thanks in advance for your advice.

Yes, it can be repaired like you request.

Yes, it can be underlapped, but it would still have patches every so often where the existing would probably break from lifting it. These would have to be patched.

Yes, you could install a tapered edge to reduce the stresses at the new-to-old transition, then shave off the protruding lip of the tapered edge to flatten it to the surface of the existing. This would help to smooth a drastic humo, but would still leave you with a hump that bucks water if the slope isnt great enough to couneract it. I would also like to see your underlap mopped in fully, and an additional 8 runs of asphalt and felt laid over the transition. If done right, this can also help to smooth the hump. Depending on the roof pitch, you might not hold any water afterall. Also, I like to see a heavy flashing (60 lb.) 18" strip mopped under the roof field, and down onto the face over the brick/siding to ensure positive drainage should a gutter strap leak, for instance.

Yes, it would be better to have gutter than trying to push water, but tapered crickets would be better than that IF you had a way of accommodating the edge of the crickets at the perimeter termination. I am assuming there is no parapet because you asked about the gutter being better.

Yes, I think it would be a great idea for you to maintain a reflective coating on you smooth BUR. This will prevent your roof from drying out and failing prematurely from UV exposure. The sun will bake your oil out of the asphalt and embrittle it. With proper maintanace and UV protection, a well-built BUR can last a VERY long time.

Hope this helps.

I forgot to mention that you would want to remove the existing coating where the patch and existing meet. I would go 4’ minimum and replace it after asphalt cures.

get a good roofer and tie it in.
make shure ya got a good couple a days no rain.
big roof make big flood inside if caught with pants down.
good luck.