On 28/07/2020 15:02, Theo wrote:
Andrew wrote:
Sounds like it has already leaked allowing the decking to weaken and
sag, hence the ponding. Complete re-decking it the solution.

That's what I suspected. Although I wondered if there was a say 5 year
shorter term fix?

Be aware that part L means it will need to be insulated and too
many roofing people will insist on adding insulation on top of the
decking and then putting the felt over the insulation. If your flat
roof is a 'cold roof' (most are) , this is s complete waste of time
since the ventilaton will still allow cold air to circulate underneath
the insulation.

This is a semi-integral garage, so I'm not sure part L applies? It's still
got a great big garage door, even if the internals are a bit nicer than a
normal garage. It isn't heated.

No, but the internal garage walls are partition walls separating garage
from living rooms/kitchen, so hopefully they will be insulated. If its
a 1960's build then insulation will be minimum.

Quoters seemed to suggest stripping it back to add insulation would be much
more than a simple re-roof.

Trying to avoid 'and while you're doing that...' project creep.

Theo

Andrew Wrote in message:
On 27/07/2020 14:20, Dave Plowman (News) wrote:
In article ,
George Miles wrote:
I've been using EDPM,
went on a one day course to learn how to do the corners.

https://www.permaroof.co.uk/rubber-roof-videos



It's easy to repair with its special primer and glues and patches, like when i dropped a slate on it.

Made by firestone , Ultra violet resistant.

Normal shed roofing only lasts a few years.

Well, this has lasted 30. So you're not doing a good job of selling an
alternative. ;-)


You said it had already been treated with something, so the actual
original probably lasted 20-25? years which is about right for a
built-up felted roof. Unless you want to reseal it with Isoflex
or whatever every 5 to 8 years thenyou might as well just get
it re-felted.

Avoid Acrypol if you have already using Isoflex, the two are
not compatible. DTDIGTTS.


DTDI...?
--
Jimk


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

On Tuesday, 28 July 2020 15:02:47 UTC+1, Theo wrote:
Andrew wrote:
Sounds like it has already leaked allowing the decking to weaken and
sag, hence the ponding. Complete re-decking it the solution.

That's what I suspected. Although I wondered if there was a say 5 year
shorter term fix?

Back in '13 or 14 we had a very bad felted roof & looked primarily at EPDM & steel. In the end a temporary job was done using bedsheets, bitumen & sand without stripping any of the damaged felt. Last time I checked it was still fine. Given that I'd take that approach again in future. Total cost was under £25 & it was quick compared to a new roof. Just wear junk clothes, they will get ruined.

Early flat roofs were deliberately ponded to increase felt life expectancy. It was soon learnt it wasn't the best idea, but it's not a game ender either. If you cover a sagging roof you take a gamble on its life expectancy, but it's £25 versus far more.


NT

wrote:
Back in '13 or 14 we had a very bad felted roof & looked primarily at EPDM
& steel. In the end a temporary job was done using bedsheets, bitumen &
sand without stripping any of the damaged felt. Last time I checked it
was still fine. Given that I'd take that approach again in future. Total
cost was under £25 & it was quick compared to a new roof. Just wear junk
clothes, they will get ruined.

Interesting, thanks. In this case it's at the front of the house so a bit
wary of conspicuous bodging...
(and DIY isn't an option in this case)

I came across:
https://job-prices.co.uk/flat-roof-cost-calculator/

which was 1.3-1.4K for a 3.5x6m flat roof with timber (optionally
insulation) in London/SE. Does that sound more plausible than the 2-3K
already quoted?

Theo

On 29/07/2020 02:55, wrote:
On Tuesday, 28 July 2020 15:02:47 UTC+1, Theo wrote:
Andrew wrote:
Sounds like it has already leaked allowing the decking to weaken and
sag, hence the ponding. Complete re-decking it the solution.

That's what I suspected. Although I wondered if there was a say 5 year
shorter term fix?

Back in '13 or 14 we had a very bad felted roof & looked primarily at EPDM & steel. In the end a temporary job was done using bedsheets, bitumen & sand without stripping any of the damaged felt. Last time I checked it was still fine. Given that I'd take that approach again in future. Total cost was under £25 & it was quick compared to a new roof. Just wear junk clothes, they will get ruined.

Early flat roofs were deliberately ponded to increase felt life expectancy. It was soon learnt it wasn't the best idea, but it's not a game ender either. If you cover a sagging roof you take a gamble on its life expectancy, but it's £25 versus far more.


NT

Flat roofs in Germany are ?always made to force ponding for some reason.
On a Grand Designs program, from many years ago, a house in East London
was given an expensive makeover with a big extension that specified a
German flat roofing system, and people came over from Germany to
do the roof. It leaked !

On Wednesday, 29 July 2020 14:13:31 UTC+1, Theo wrote:
tabbypurr wrote:

Back in '13 or 14 we had a very bad felted roof & looked primarily at EPDM
& steel. In the end a temporary job was done using bedsheets, bitumen &
sand without stripping any of the damaged felt. Last time I checked it
was still fine. Given that I'd take that approach again in future. Total
cost was under £25 & it was quick compared to a new roof. Just wear junk
clothes, they will get ruined.

Interesting, thanks. In this case it's at the front of the house so a bit
wary of conspicuous bodging...
(and DIY isn't an option in this case)

It looks the same as any felt roof. The finish used was sand, you can also get stone waste for a nicer look. That would up the cost to near £30 though


NT

On 26/07/2020 18:20, Dave Plowman (News) wrote:
Big snag is actually knowing how long these 'new' methods do last. Plenty
claims, though. The decking is marine ply, so hoping it will still be
just fine. The chippie who did the work was very good indeed.

Marine ply won't disintegrate if it gets wet - it'll just dry again.

Unless it keeps getting wet, when it will rot just like any other wood.

Andy

On Thursday, 30 July 2020 21:58:01 UTC+1, Vir Campestris wrote:
On 26/07/2020 18:20, Dave Plowman (News) wrote:

Big snag is actually knowing how long these 'new' methods do last. Plenty
claims, though. The decking is marine ply, so hoping it will still be
just fine. The chippie who did the work was very good indeed.

Marine ply won't disintegrate if it gets wet - it'll just dry again.

Unless it keeps getting wet, when it will rot just like any other wood.

Andy

Marine ply is one of those things much talked about but never seen in diy or pro house maintenance. If someone says marine ply, it's something else.


NT

In article ,
wrote:
On Thursday, 30 July 2020 21:58:01 UTC+1, Vir Campestris wrote:
On 26/07/2020 18:20, Dave Plowman (News) wrote:

Big snag is actually knowing how long these 'new' methods do last.
Plenty claims, though. The decking is marine ply, so hoping it will
still be just fine. The chippie who did the work was very good
indeed.

Marine ply won't disintegrate if it gets wet - it'll just dry again.

Unless it keeps getting wet, when it will rot just like any other wood.

Andy

Marine ply is one of those things much talked about but never seen in
diy or pro house maintenance. If someone says marine ply, it's something
else.


Most timber yards round here sell it. Or rather what they call marine ply.
At about 5 times the price of general purpose stuff.

--
*What was the best thing before sliced bread?

Dave Plowman London SW
To e-mail, change noise into sound.

On 31/07/2020 14:22:14, Dave Plowman (News) wrote:
In article ,
wrote:
On Thursday, 30 July 2020 21:58:01 UTC+1, Vir Campestris wrote:
On 26/07/2020 18:20, Dave Plowman (News) wrote:

Big snag is actually knowing how long these 'new' methods do last.
Plenty claims, though. The decking is marine ply, so hoping it will
still be just fine. The chippie who did the work was very good
indeed.

Marine ply won't disintegrate if it gets wet - it'll just dry again.

Unless it keeps getting wet, when it will rot just like any other wood.

Andy

Marine ply is one of those things much talked about but never seen in
diy or pro house maintenance. If someone says marine ply, it's something
else.


Most timber yards round here sell it. Or rather what they call marine ply.
At about 5 times the price of general purpose stuff.

If you want to go to the extreme make sure the marine ply it is of the
WBF type. A further extreme is to get Buffalo board. I've used it on a
shed roof without felt. My experience is it lasts 25 years in the open
air environment and is still serviceable and waterproof.

Dave Plowman (News) wrote:

wrote:

Marine ply is one of those things much talked about but never seen in
diy or pro house maintenance. If someone says marine ply, it's something
else.

Most timber yards round here sell it. Or rather what they call marine ply.
At about 5 times the price of general purpose stuff.

sure it's not WBP?

On Friday, 31 July 2020 15:54:40 UTC+1, Andy Burns wrote:
Dave Plowman (News) wrote:
tabbypurr wrote:

Marine ply is one of those things much talked about but never seen in
diy or pro house maintenance. If someone says marine ply, it's something
else.

Most timber yards round here sell it. Or rather what they call marine ply.
At about 5 times the price of general purpose stuff.

sure it's not WBP?

On a good day it will be. But beware that WBP has no legal meaning now, anything marked WBP can delaminate after a single light shower. DAMHIKT.


NT

In article ,
Andy Burns wrote:
Dave Plowman (News) wrote:

wrote:

Marine ply is one of those things much talked about but never seen in
diy or pro house maintenance. If someone says marine ply, it's
something else.

Most timber yards round here sell it. Or rather what they call marine
ply. At about 5 times the price of general purpose stuff.

sure it's not WBP?

I'd say you'd have to ask them. ;-)

--
*I couldn't repair your brakes, so I made your horn louder *

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
wrote:
On Friday, 31 July 2020 15:54:40 UTC+1, Andy Burns wrote:
Dave Plowman (News) wrote:
tabbypurr wrote:

Marine ply is one of those things much talked about but never seen
in diy or pro house maintenance. If someone says marine ply, it's
something else.

Most timber yards round here sell it. Or rather what they call
marine ply. At about 5 times the price of general purpose stuff.

sure it's not WBP?

On a good day it will be. But beware that WBP has no legal meaning now,
anything marked WBP can delaminate after a single light shower. DAMHIKT.


Not sure I'd be happy paying all that money for something advertised on
their web site as marine ply to find it was something different?

Of course it's a trick some roofers etc might do. Charge you for marine
ply and use something cheaper.

--
*What was the best thing before sliced bread? *

Dave Plowman London SW
To e-mail, change noise into sound.

On Friday, 31 July 2020 19:09:26 UTC+1, Dave Plowman (News) wrote:
In article ,
tabbypurr wrote:
On Friday, 31 July 2020 15:54:40 UTC+1, Andy Burns wrote:
Dave Plowman (News) wrote:
tabbypurr wrote:

Marine ply is one of those things much talked about but never seen
in diy or pro house maintenance. If someone says marine ply, it's
something else.

Most timber yards round here sell it. Or rather what they call
marine ply. At about 5 times the price of general purpose stuff.

sure it's not WBP?

On a good day it will be. But beware that WBP has no legal meaning now,
anything marked WBP can delaminate after a single light shower. DAMHIKT.


Not sure I'd be happy paying all that money for something advertised on
their web site as marine ply to find it was something different?

Of course it's a trick some roofers etc might do. Charge you for marine
ply and use something cheaper.

You wouldn't be the first to be not too happy. In most cases purchasers never find out. If you ask for or accept 'marine ply' you're letting them know you're gullible.


NT

In article ,
wrote:
On Friday, 31 July 2020 19:09:26 UTC+1, Dave Plowman (News) wrote:
In article ,
tabbypurr wrote:
On Friday, 31 July 2020 15:54:40 UTC+1, Andy Burns wrote:
Dave Plowman (News) wrote:
tabbypurr wrote:

Marine ply is one of those things much talked about but never
seen in diy or pro house maintenance. If someone says marine
ply, it's something else.

Most timber yards round here sell it. Or rather what they call
marine ply. At about 5 times the price of general purpose stuff.

sure it's not WBP?

On a good day it will be. But beware that WBP has no legal meaning
now, anything marked WBP can delaminate after a single light shower.
DAMHIKT.


Not sure I'd be happy paying all that money for something advertised
on their web site as marine ply to find it was something different?

Of course it's a trick some roofers etc might do. Charge you for
marine ply and use something cheaper.

You wouldn't be the first to be not too happy. In most cases purchasers
never find out. If you ask for or accept 'marine ply' you're letting
them know you're gullible.


This particular job was designed and overseen by an architect who is not
only very good, but a friend. Using the builders he used on many other
jobs and recommended. I also watched much of it being done. I'd be rather
surprised if he was happy with other than what he specified being used. On
occasions where the builders wanted the spec changed, there were
discussions all round about them.

--
*Don't worry; it only seems kinky the first time.*

Dave Plowman London SW
To e-mail, change noise into sound.

wrote:

On Friday, 31 July 2020 19:09:26 UTC+1, Dave Plowman (News) wrote:
In article ,
tabbypurr wrote:
On Friday, 31 July 2020 15:54:40 UTC+1, Andy Burns wrote:
Dave Plowman (News) wrote:
tabbypurr wrote:

Marine ply is one of those things much talked about but never seen
in diy or pro house maintenance. If someone says marine ply, it's
something else.

Most timber yards round here sell it. Or rather what they call
marine ply. At about 5 times the price of general purpose stuff.

sure it's not WBP?

On a good day it will be. But beware that WBP has no legal meaning now,
anything marked WBP can delaminate after a single light shower. DAMHIKT.


Not sure I'd be happy paying all that money for something advertised on
their web site as marine ply to find it was something different?

Of course it's a trick some roofers etc might do. Charge you for marine
ply and use something cheaper.

You wouldn't be the first to be not too happy. In most cases purchasers
never find out. If you ask for or accept 'marine ply' you're letting them
know you're gullible.


NT

As a matter of interest, what can you specifiy nowadays if you want
waterproof plywood?
--

Roger Hayter

On Saturday, 1 August 2020 12:24:11 UTC+1, Roger Hayter wrote:
tabbypurr wrote:
On Friday, 31 July 2020 19:09:26 UTC+1, Dave Plowman (News) wrote:
In article ,
tabbypurr wrote:
On Friday, 31 July 2020 15:54:40 UTC+1, Andy Burns wrote:
Dave Plowman (News) wrote:
tabbypurr wrote:

Marine ply is one of those things much talked about but never seen
in diy or pro house maintenance. If someone says marine ply, it's
something else.

Most timber yards round here sell it. Or rather what they call
marine ply. At about 5 times the price of general purpose stuff.

sure it's not WBP?

On a good day it will be. But beware that WBP has no legal meaning now,
anything marked WBP can delaminate after a single light shower. DAMHIKT.


Not sure I'd be happy paying all that money for something advertised on
their web site as marine ply to find it was something different?

Of course it's a trick some roofers etc might do. Charge you for marine
ply and use something cheaper.

You wouldn't be the first to be not too happy. In most cases purchasers
never find out. If you ask for or accept 'marine ply' you're letting them
know you're gullible.


NT

As a matter of interest, what can you specifiy nowadays if you want
waterproof plywood?

https://www.contractflooringjournal....-thing-as-wbp/


NT

wrote:

On Saturday, 1 August 2020 12:24:11 UTC+1, Roger Hayter wrote:
snip
NT

As a matter of interest, what can you specifiy nowadays if you want
waterproof plywood?

https://www.contractflooringjournal....d-there-is-no-
such-thing-as-wbp/


NT

Thanks, that's helpful. But doesn't help with the elusive marine
plywood which is allowed to be wet! Perhaps it never existed.

--

Roger Hayter

Roger Hayter wrote:

doesn't help with the elusive marine
plywood which is allowed to be wet! Perhaps it never existed.

See BS 1088:2018 and friends

In message , Roger Hayter
writes
wrote:

On Saturday, 1 August 2020 12:24:11 UTC+1, Roger Hayter wrote:
snip
NT

As a matter of interest, what can you specifiy nowadays if you want
waterproof plywood?

https://www.contractflooringjournal....d-there-is-no-
such-thing-as-wbp/


NT

Thanks, that's helpful. But doesn't help with the elusive marine
plywood which is allowed to be wet! Perhaps it never existed.

I vaguely thought the special feature of marine ply beyond waterproof
glue was the lack of *voids* in the laminations.

I once watched normal plywood being made at a factory in Boise, Idaho.
Strips of glue were mechanically applied before workers *threw* hand
broken strips of laminate to cover the worst of the voids before the
next sheet of laminate was moved into position.

I think marine ply must use knot free timber stock.


--
Tim Lamb

On Sun, 2 Aug 2020 10:37:25 +0100, Roger Hayter wrote:

Thanks, that's helpful. But doesn't help with the elusive marine
plywood which is allowed to be wet! Perhaps it never existed.

Well some form of ply wood existed that didn't fall apart when it got
wet. There was a bit here, untreated/paintted, used as a sign propped
up against a wall so lower edge on the ground that was still sound
after a couple of years. Bit moss and algae covered mind...

--
Cheers
Dave.

On 02/08/2020 10:37:25, Roger Hayter wrote:
wrote:

On Saturday, 1 August 2020 12:24:11 UTC+1, Roger Hayter wrote:
snip
NT

As a matter of interest, what can you specifiy nowadays if you want
waterproof plywood?

https://www.contractflooringjournal....d-there-is-no-
such-thing-as-wbp/


NT

Thanks, that's helpful. But doesn't help with the elusive marine
plywood which is allowed to be wet! Perhaps it never existed.

I'm not sure if it did. As I have said earlier the closest you can get
in buffalo boards that I have seen weather outside for 30+ years. They
were still sound and were showing their age more from a cosmetic point
of view. I have also seen marine ply last 30 years as a narrowboat
floor. One side would have been exposed to a wet bilge. Some areas were
becoming soggy.

In terms of specs there are some BS and ISO number as indicated by
various links in this thread.

But for total immersion I might use plastics like:

https://www.kedel.co.uk/mixed-plasti...50-x-50mm.html

Not cheap.

OSB of the right grade is used in houses where the panel is subject to
moisture, but again not immersion.

On Sunday, 2 August 2020 10:37:27 UTC+1, Roger Hayter wrote:
tabbypurr wrote:
On Saturday, 1 August 2020 12:24:11 UTC+1, Roger Hayter wrote:
snip
NT

As a matter of interest, what can you specifiy nowadays if you want
waterproof plywood?

https://www.contractflooringjournal....d-there-is-no-
such-thing-as-wbp/


NT

Thanks, that's helpful. But doesn't help with the elusive marine
plywood which is allowed to be wet! Perhaps it never existed.

Standard stuff on boats. I thought the wiki addressed the new classes in one of the links.


NT

On Sunday, 2 August 2020 11:38:22 UTC+1, Dave Liquorice wrote:
On Sun, 2 Aug 2020 10:37:25 +0100, Roger Hayter wrote:

Thanks, that's helpful. But doesn't help with the elusive marine
plywood which is allowed to be wet! Perhaps it never existed.

Well some form of ply wood existed that didn't fall apart when it got
wet. There was a bit here, untreated/paintted, used as a sign propped
up against a wall so lower edge on the ground that was still sound
after a couple of years. Bit moss and algae covered mind...

WBP or shuttering ply


NT