Thread: Glue, fill and seal timber joints coated in bitumen paint?

Hi and welcome to the forum,
Other than bitumen I cant think of any. That said a roof needs to let water run off. Gaps that hold water are not a good idea. If your gaps run up and down then cover them with a strip of ply. If they are horizontal they will just hold water and cause leaking and rot. Filling gaps on a roof with anything will only ever be a short term fix. Easiest or best fix would be cover the whole lot with colorbond roofing sheets or similar.
Regards
John

Firstly, what was the "bitumen based paint" exactly? (inc. brand), Also, what is the 3-1 sealer/filler/glue?

I suspect that you're out of luck. Nothing really sticks to bitumen except more bitumen and trying to remove it is a PITA. Even if you scrape the area clean and use a solvent to clean the surface, enough contamination penetrates into the timber that the problem persists.

Originally Posted by orraloon

If your gaps run up and down then cover them with a strip of ply. If they are horizontal they will just hold water and cause leaking and rot.

If the crack is horizontal, I'd lift the top sheet and move it down a cm or three so that it overlaps, shingle style. If it's a peaked roof, the capping should cover the now larger gap along the ridge line.

As you've already bitumened, it wouldn't hurt to lather on fresh bitumen instead of glue/sealant to seal overlapped joints, provided you also securely fasten them down with clouts/screws/whatever.

Depending on what bituminous product you have used there are a couple of options
You can can a trowelable bitumen in 1 or 4 litre tins that you could use with a broad knife or you can also get them in a tube that you could apply to the joints with a caulking gun

The first thing is to establish what product you have used and seek advice from manufacturer for recommendations of what is compatible

Sikaflex pro, available in black, will stick to the bitumen

If it is similar the water-based bitumen that I have used it will oxidise fairly quickly in direct sunlight.

In (too) many places where I have painted over the bitumen with grey Solarguard (to stop the oxidation) the grey paint has bubbled. I have never been able to make any sense of this because:
the bitumen is for putting a waterproof membrane on (and can be used for potable water) so you'd kinda think it is waterproof, cos it says "Waterproof"
where it is just bitumen there is no bubbling
where it is just paint there is no bubbling
the paint doesn't always bubble on the bitumen
this was on treated pine (sleepers and posts) which was nowhere near dry, so I get that there is moisture wanting to escape, but......

Originally Posted by rwbuild

Sikaflex pro, available in black, will stick to the bitumen

Yes, I have had success with this. Sikaflex will also oxidise in sunlight, but can be readily painted.

Hi,
It's just an animal shelter, not a human dwelling, so I was planning just to use marine plywood coated in the bitumen paint.
Gaps are 12° away from horizontal down beneath the outer edges of the single top sheet (but thin), and near vertical down between the side pieces around the edges (but wider).
So far I've had recommended either tar putty or polyurethane sealant.
Gee, this forum is so helpful it's hard to keep up with the replies.
Thanks!

The marine plywood is coated with "Diggers Eco In-Ground Protecta" (a water-based bitumen paint), and the glue that's not sticking to it is "Selleys Ezi Press 3in1 sealant, adhesive & gap filler" (a "hybrid polymer").
Thanks!

This is Sikas version
https://www.bunnings.com.au/sika-aus...alant_p1220007 but there are a number of other brands

Originally Posted by WoodyWoodWood

The marine plywood is coated with "Diggers Eco In-Ground Protecta" (a water-based bitumen paint)

Right, there is the problem right there! Teats on a bull useless, it is (DAMHIKT). I'd sand it off as much as possible and start again. Seal the end grain with Sikaflex Pro (dip your finger in turps to get a nice smooth edge) and just paint it with Solarguard or similar.

Hi Beardy,
Thanks! It works!
Just a note of caution for anyone reading this in the future: this stuff never fully sets, but remains slightly gooey and sticky and stains anything that touches it.
Even the "Diggers Eco In-Ground Protecta" can remain a little sticky and stainy if painted on too thick.
Thanks again!