Small tar bubbles

Hi there,

I am new here.
I am from Montreal Quebec,apologies then for my bad or unclear english.

I have a 1400sq m. flat roof made of tar and gravel.It’s quite old. But had never leaked.
I am planning to change the roof next year, using TPO or EPDM.

I regularly go on my roof to check for any problems.
Last autumn, I 've patched all the flashings have been sealed and painted. I have also had some gravel here and there where needed.

It has been really hot here in the last days,
I have seen some little bubbles, that are at the surface of the roof, they are detached, mixed with the gravel and of the size of little strawberries, sometimes smaller sometimes bigger…

Is that something I have to be worried about ??

I 'll try to take some photos to show you,

thanks

Greg

greg, thats nothing to worry about.its just a sign of the type of tar that was used on your roof. that would be what we call pitch, or some call coal tar pitch. a real good roof, self sealing when the sun heats it up. thats probably why you havent had any problems.

roofboss/rooferj you trying to kill this poor candian :twisted:

LOL! Nah, I like to hang out by the kettle myself and look in at the pretty yellowish-green smoke every now and then! After that, I like to try and drive home with my eyes half-opened! :wink:

[quote=“gregvdd”]Hi there,

I am new here.
I am from Montreal Quebec,apologies then for my bad or unclear english.

I have a 1400sq m. flat roof made of tar and gravel.It’s quite old. But had never leaked.
I am planning to change the roof next year, using TPO or EPDM.

I regularly go on my roof to check for any problems.
Last autumn, I 've patched all the flashings have been sealed and painted. I have also had some gravel here and there where needed.

It has been really hot here in the last days,
I have seen some little bubbles, that are at the surface of the roof, they are detached, mixed with the gravel and of the size of little strawberries, sometimes smaller sometimes bigger…

Is that something I have to be worried about ??

I 'll try to take some photos to show you,

thanks

Greg[/quote]

Seriously, if you have a coal-tar pitch roof and it hasn’t been leaking, why are you thinking of replacing it? I was involved in a tear-off of an old CTP roof in Baltimore, Md. years ago, and underneath the roof system we found the society pages from the late 1920’s. That roof was over 50 years old!

As for the bubbles, as others have pointed out it is normal, especially with extreme heat. What is happening is the CTP has become somewhat viscous and the stone aggregate has started to sink into the flood coat of CTP.

Meanwhile, what you can’t see going on is the migration of inter-ply moppings of CTP starting to migrate out from the built-up membrane. The good news is with CTP unlike asphalt, the CTP itself is viewed as the waterproofing agent, whereas with asphalt it is the sandwich created by the build up of plies and asphalt.

So, once again, if it isn’t leaking, I don’t know that I would f*** with the roof unless you are just dying to spend some money or need a write-off. Do you have any photos? How old is “quite old”?

Cerberus, is the Latin variation of the proper Greek spelling of Kerberos.

Greek Mythology: The three-headed dog that guarded the Gates of Hades.

If it’s not leaking don’t replace it. As far as putting a tpo or epdm roof on in its place consider a urethane foam roof. It’s a little cheaper and has great Insulating value will save you money on utillitys and will pay for it’s self

That all depends on where he lives. Personally, I don’t care for foam, but it has its place in the industry. For example, in Arizona where you don’t have much rain but have lots of sun, it makes sense. On the other hand, I wouldn’t even consider foam in Chicago, D.C. or N.Y. with their climate.

Chew the tar dammit !

may be blisters in granulated surface.
pics yes.

gweedo.