Son has had to change priorities because of the weather and a flat roof
leak in his main house (as opposed to the garden things I usually ask
about).
It's a small roof about 20 x 4 feet, and one possible problem is that
one long edge is pretty tight up underneath the overhanging main tiled
roof of the house.

He has decided to replace the old felt with a fibreglass roof and has
bought the resin and glass as a kit, so we hope everything is there.

He says the roof feels very spongy when he stands on it, and the leak
has obviously been there for quite a long time, so we decided to get in
replacement roof boarding.

I rang the local wood yard about OSB3 roof decking and they offered
Metsa Wood Roofdeck, which says it is OSB3, which my reading seem to
suggest is OSB2 with some sort of coating.

What we didn't expect was that the boards are wood coloured on one side,
but the other side and edges are black, and covered with a sort of very
thin cellophany film.

So, to the stupid question, which way up should these boards go? Black
or woody? And should we take off the film before we put them in place.
Presumably on the top, the resin ought to soak into the wood a little.

Any suggestions re doing this sort of roof gratefully received. We won't
be starting for a few weeks because he is stuck camping at work because
of the Olympics.
--
Bill

Bill wrote:
Son has had to change priorities because of the weather and a flat
roof leak in his main house (as opposed to the garden things I
usually ask about).
It's a small roof about 20 x 4 feet, and one possible problem is that
one long edge is pretty tight up underneath the overhanging main tiled
roof of the house.

He has decided to replace the old felt with a fibreglass roof and has
bought the resin and glass as a kit, so we hope everything is there.

He says the roof feels very spongy when he stands on it, and the leak
has obviously been there for quite a long time, so we decided to get
in replacement roof boarding.

I rang the local wood yard about OSB3 roof decking and they offered
Metsa Wood Roofdeck, which says it is OSB3, which my reading seem to
suggest is OSB2 with some sort of coating.

What we didn't expect was that the boards are wood coloured on one
side, but the other side and edges are black, and covered with a sort
of very thin cellophany film.

So, to the stupid question, which way up should these boards go? Black
or woody? And should we take off the film before we put them in place.
Presumably on the top, the resin ought to soak into the wood a little.

Any suggestions re doing this sort of roof gratefully received. We
won't be starting for a few weeks because he is stuck camping at work
because of the Olympics.

Black side up...you may or may not get the film off, but feel free to give
it a whirl.

The bitumen is there to protect the timbers during construction, IE if you
get it all boarded, and then it ****es it down for a fortnight, not that
that ever occurs in the UK...normal boarding would probably get water
damaged

In message , Phil L
writes
Bill wrote:

What we didn't expect was that the boards are wood coloured on one
side, but the other side and edges are black, and covered with a sort
of very thin cellophany film.

So, to the stupid question, which way up should these boards go? Black
or woody? And should we take off the film before we put them in place.
Presumably on the top, the resin ought to soak into the wood a little.

Any suggestions re doing this sort of roof gratefully received. We
won't be starting for a few weeks because he is stuck camping at work
because of the Olympics.

Black side up...you may or may not get the film off, but feel free to give
it a whirl.

The bitumen is there to protect the timbers during construction, IE if you
get it all boarded, and then it ****es it down for a fortnight, not that
that ever occurs in the UK...normal boarding would probably get water
damaged


I can understand this for situations where boiling tar is the next
substance to be applied, but does this work with fibreglass resin? Would
the resin soak into the black bitumen surface as is needed to make what
is essentially a composite roof?

I assume that we really have to take the film off, unless that dissolves
in resin. I can't seem to find any manufacturer's data sheet about this
Metsa board, just brochures that say it's wonderful. I could only
inspect the boards today in half-light as I didn't have the key to the
shed, but the black looks like more a matt paint than any sort of
bitumen I've ever seen.

As is obvious, I haven't ever done a roof before.

Because the roof is 4 feet wide and it's all we could find locally, we
have bought the 8x4 sheets rather than the 8x2 t&g that seems to be
suggested. I assume this means we have to allow for expansion at the
edges, but I don't really understand how this works as we then bond the
whole lot solidly together.

--
Bill

On Jul 24, 11:49*pm, Bill wrote:
In message , Phil L
writes

Bill wrote:

What we didn't expect was that the boards are wood coloured on one
side, but the other side and edges are black, and covered with a sort
of very thin cellophany film.

So, to the stupid question, which way up should these boards go? Black
or woody? And should we take off the film before we put them in place.
Presumably on the top, the resin ought to soak into the wood a little.

Any suggestions re doing this sort of roof gratefully received. We
won't be starting for a few weeks because he is stuck camping at work
because of the Olympics.

Black side up...you may or may not get the film off, but feel free to give
it a whirl.

The bitumen is there to protect the timbers during construction, IE if you
get it all boarded, and then it ****es it down for a fortnight, not that
that ever occurs in the UK...normal boarding would probably get water
damaged

I can understand this for situations where boiling tar is the next
substance to be applied, but does this work with fibreglass resin? Would
the resin soak into the black bitumen surface as is needed to make what
is essentially a composite roof?

I assume that we really have to take the film off, unless that dissolves
in resin. I can't seem to find any manufacturer's data sheet about this
Metsa board, just brochures that say it's wonderful. I could only
inspect the boards today in half-light as I didn't have the key to the
shed, but the black looks like more a matt paint than any sort of
bitumen I've ever seen.

As is obvious, I haven't ever done a roof before.

Because the roof is 4 feet wide and it's all we could find locally, we
have bought the 8x4 sheets rather than the 8x2 t&g that seems to be
suggested. I assume this means we have to allow for expansion at the
edges, but I don't really understand how this works as we then bond the
whole lot solidly together.


Just about nothing will bond to bitumen or polythene, or several other
plastics.

I've done felted shed roofs with WBP ply and basic chipboard, and the
difference in life expectancy is minimal. Once the felt fails, it
won't last much longer whatever's underneath. You might get another 12
months from good stuff, but its not worth it on a per year basis. TBH
you'd probably get more life out of sliced hardwood firewood than any
treated softwood. Last time I looked an ebay seller was selling large
quantities of sawmill reject oak for 200 a batch.


NT

Bill wrote:
I can understand this for situations where boiling tar is the next
substance to be applied, but does this work with fibreglass resin?
Would the resin soak into the black bitumen surface as is needed to
make what is essentially a composite roof?


Highly unlikely even with untreated wood.
All wood will shrink and move a lot more than the fibreglass, so any 'bond'
wouldn't last very long, but it's not important.

I assume that we really have to take the film off, unless that
dissolves in resin. I can't seem to find any manufacturer's data
sheet about this Metsa board, just brochures that say it's wonderful.
I could only inspect the boards today in half-light as I didn't have
the key to the shed, but the black looks like more a matt paint than
any sort of bitumen I've ever seen.

As is obvious, I haven't ever done a roof before.

Because the roof is 4 feet wide and it's all we could find locally, we
have bought the 8x4 sheets rather than the 8x2 t&g that seems to be
suggested. I assume this means we have to allow for expansion at the
edges, but I don't really understand how this works as we then bond
the whole lot solidly together.

You don't need to allow for expansion, just nail or screw the boards on,
apply the fibreglass and forget about it