Recoating shed roof with bitumen paint?
 

I have a shed covered with tongue-and-groove cladding, which I've
repainted on the outside since it was built.

The roof is the same material but covered with roofing felt. I'd like
to make the roof last a long time and I happen to have some bitumen
paint lying around --- would putting a few coats of this on the
roofing felt every few years be a good way of extending its
durability?

Thanks,
Adam

Recoating shed roof with bitumen paint?
 

On Wed, 6 Dec 2006 12:24:22 +0000, Adam Funk wrote:

The roof is the same material but covered with roofing felt. I'd like
to make the roof last a long time and I happen to have some bitumen
paint lying around --- would putting a few coats of this on the
roofing felt every few years be a good way of extending its
durability?

Yes, though the paint doesn't last too well. Keep the brush/roller in a
near-empty tin of bit paint for next year. Or wrap it in plastic, and stick it
in the paint a few days before you use it next. It will stiffen up a bit, but
soften in while if immersed in the paint. Not worth the mess to wash it out.

The paint comes off hands etc very well with baby oil, or oil-soaked baby bum
wipes. Skin-friendlier and less smelly than diesel...

Thomas Prufer

Recoating shed roof with bitumen paint?
 

Adam Funk wrote:
I have a shed covered with tongue-and-groove cladding, which I've
repainted on the outside since it was built.

The roof is the same material but covered with roofing felt. I'd like
to make the roof last a long time and I happen to have some bitumen
paint lying around --- would putting a few coats of this on the
roofing felt every few years be a good way of extending its
durability?

Thanks,
Adam

If you want it to last a long tiime buy a Butyl pond liner and use that
as a roofing membrane, it'll go for 30 years or more !! I have two
sheds/utillity room done like this with ply underneath, works a treat
!!
got mine from www.pondlinersdirect.co.uk

Recoating shed roof with bitumen paint?
 

On 6 Dec 2006 06:41:03 -0800, "Staffbull" wrote:

If you want it to last a long tiime buy a Butyl pond liner and use that
as a roofing membrane, it'll go for 30 years or more !! I have two
sheds/utillity room done like this with ply underneath, works a treat
!!

Ack. Felt's not all that great, as UV breaks down the bitumen eventually.

Neighbor tossed a thick layer of sand on his ancient felt roof when he painted
his with bituminous paint. It has extended the life considerably -- the layer of
sand seems to protect the paint. His roof is fairly steep, though, I'd worry
that stuff would stick to the sand layer if it were flattish -- though moss
should protect form UV as well?


Thomas Prufer

Recoating shed roof with bitumen paint?
 

On 2006-12-06, Thomas Prufer wrote:

Yes, though the paint doesn't last too well.

Do you mean a tin of it, once opened, doesn't last long even stored
properly? In that case, I'd better look in the old tin before I get
set up to use it....


The paint comes off hands etc very well with baby oil, or oil-soaked baby bum
wipes. Skin-friendlier and less smelly than diesel...

I find disposable rubber gloves are worthwhile for painting (even with
normal paint).

Recoating shed roof with bitumen paint?
 

On 2006-12-06, Thomas Prufer wrote:

Ack. Felt's not all that great, as UV breaks down the bitumen eventually.

Neighbor tossed a thick layer of sand on his ancient felt roof when he painted
his with bituminous paint. It has extended the life considerably -- the layer of
sand seems to protect the paint. His roof is fairly steep, though, I'd worry
that stuff would stick to the sand layer if it were flattish -- though moss
should protect form UV as well?

This one's not steep at all, although there's nothing growing on it
yet (a few years after installation).

Recoating shed roof with bitumen paint?
 

On Thu, 14 Dec 2006 11:50:51 +0000, Adam Funk wrote:

Do you mean a tin of it, once opened, doesn't last long even stored
properly? In that case, I'd better look in the old tin before I get
set up to use it....

Oh no, the tin lasts a long time. And I think any old solvent would do to thin
the stuff if it had dried up a bit. Let it get good and warm give it a good
stir, and off you go.

I meant that the bitumen paints I've used all have weathered off fairly quickly.
There's a few that supposedly last a lot longer: some sort of water-soluble
acrylic roof paint, or two-pack epoxy stuff. One look at the label: coverage
rates and the price tag mean that I can either put up a new roof for the money,
or keep the money and slap paint on every two years or so.


Thomas Prufer

Recoating shed roof with bitumen paint?
 

On 2006-12-06, Staffbull wrote:

If you want it to last a long tiime buy a Butyl pond liner and use that
as a roofing membrane, it'll go for 30 years or more !! I have two
sheds/utillity room done like this with ply underneath, works a treat
!!
got mine from www.pondlinersdirect.co.uk

I'll look into that; thanks.

Recoating shed roof with bitumen paint?
 

On 2006-12-14, Thomas Prufer wrote:

Oh no, the tin lasts a long time. And I think any old solvent would do to thin
the stuff if it had dried up a bit. Let it get good and warm give it a good
stir, and off you go.

I meant that the bitumen paints I've used all have weathered off fairly quickly.
There's a few that supposedly last a lot longer: some sort of water-soluble
acrylic roof paint, or two-pack epoxy stuff. One look at the label: coverage
rates and the price tag mean that I can either put up a new roof for the money,
or keep the money and slap paint on every two years or so.

Thanks for the info. I'll look into the butyl pond liner, or else
"reinforce" the bitumen paint with sand.

Recoating shed roof with bitumen paint?
 

Adam Funk wrote:

would putting a few coats of this on the
roofing felt every few years be a good way of extending its
durability?

No. The felt fails because the felt itself goes brittle and cracks,
not through the failure of any surface waterproofing layer that could
be restored by painting it.

The main culprit here is UV radiation, so anything you do at
construction time that reduces this can be useful. Sand coated felt, or
even painting it white, will help. Bitumen roofing felt already has
plenty of bitumen in it though, so painting more on doesn't add
anything.

A coat of bitumen paint on the timber underneath is useful though. This
helps to protect the wood from any moisture that does find its way
under.

Recoating shed roof with bitumen paint?
 

On 2006-12-18, Andy Dingley wrote:

No. The felt fails because the felt itself goes brittle and cracks,
not through the failure of any surface waterproofing layer that could
be restored by painting it.

The main culprit here is UV radiation, so anything you do at
construction time that reduces this can be useful. Sand coated felt, or
even painting it white, will help. Bitumen roofing felt already has
plenty of bitumen in it though, so painting more on doesn't add
anything.

So the only real solution is to replace the exposed felt occasionally...

A coat of bitumen paint on the timber underneath is useful though. This
helps to protect the wood from any moisture that does find its way
under.

....and do this. Or use the butyl rubber pond liner, as someone else
has suggested.

I take it roofing felt *in a roof* lasts a long time because the
slates protect it from the UV rays?