timber frame house

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richardbrown

richardbrown

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I am looking at a job tomorrow which is a timber frame house that they want a insulated thin coat system fitted to. when they are ready for me the house will be covered in ply.

What would the spec for this be, I cant seem to find any information on this on the marmorit website.

Could I fit the insulation directly to the plywood or should a rail system be fitted.

Any information would be appreciated
Rich
 
Breather membrane over the OSB, possible slip joints required if over two storeys or if architect specifies.

Cavity rail insulation required only when architect specified.

Generally insulation directly applied to breather barrier. We've done a fair bit like this and it is still warrantable(sp)
 
richardbrown said:
so plywood, breather membrane then insulation fixed with mushroom fixings directly into the ply
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Insulation washers with ss screws, last thing you need is the screw heads bleeding through a thin coat system. Coated screws are ok but they only give you a max 1000hrs exposure and wont be covered for use in most systems.
 
Direct Building Supplies do the screw in mushroom heads and the screws. 01274720905.
 
Rigsby said:
Direct Building Supplies do the screw in mushroom heads and the screws. 01274720905.
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Bit of an awkward one this. Some manufacturers want a air gap between the ply board and insulation which defeats the object. If the insulation is breathable then why not direct fit on breathable felt?
 
You cannot fit the insulation to directly to the ply on this type of building rich if the ply is fixed directly to the frame. You have to have a cavity. you can use either a rail system or simple counter battens.

one way is to have the just cavity off the subframe and then sheath with cemboard or if the ply is fixed directly to the timber frame which it sounds like this is you will need to create a cavity then insulate.

Using counter battens will usually mean you then need to sheath afterwards in order to provide a carrier for the insulation cover your cost coz these systems need extra care to openings. marmorit have a system and I would get them in to spec it fully because it will need passing to get all the NHBC/BRE/TRADA/MORTGAGE bumf.

Get the rep to fully spec and guarantee this Rich along with having a contract that rules you out of any design liability, thats if they want a nasty contract on the job
 
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Rigsby said:
Bit of an awkward one this. Some manufacturers want a air gap between the ply board and insulation which defeats the object. If the insulation is breathable then why not direct fit on breathable felt?
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Not manufacturers that make the rules mate they just following them

Its the Regs for this build type

the subframe must be vented
 
thanks John.

as it turns out I have been asked today to provide the render only as the builder wants to fit all the insulation and cem board himself so I dont have to worry about it.
Everyone tells me different things lol
 
richardbrown said:
thanks John.

as it turns out I have been asked today to provide the render only as the builder wants to fit all the insulation and cem board himself so I dont have to worry about it.
Everyone tells me different things lol
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thats sorted then mate, not for you to worry about unless he reads nbs and assumes you are going for the insulation suspended on rails

assuming he follows NHBC regs he will soon find out he needs the cavity otherwise the property will be UN-mortgagable etc

anyhow as long as you in clear. Marmo have all the gear anyways love
 
This scenario seems a good place for some sort of new board like kingspan kooltherm k5 but with vertical grooves in the back for drainage. Screw em directly on with stainless mushrooms and bob's ur muncle like
 
You couldn't carry the boards it'd be like trying to carry round an 8 foot concertina lol or it'd be mint you could roll them up and carry one under each arm
 
Or you could cut a hole fit some perspex and have a lovely cloche For you're winter lettuce
 
goody said:
This scenario seems a good place for some sort of new board like kingspan kooltherm k5 but with vertical grooves in the back for drainage. Screw em directly on with stainless mushrooms and bob's ur muncle like
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you can'i like coz all timber subframes have to have a cleared ventilated cavity continuous of a min (20 or 25mm cant remember exactly). The whole reason behind it is to protect the frame for a period of time to allow building regs such as insurance/nhbc/mortgage etc. they started out direct fitting systems in the first place only to discover a heap of failed frames rotting away due to water tracing/tracking because of closed contact with the facades so they banned the use (except for sheds and the like)
 
Yep I still don't know what a cloche is ha
Fair play plaster j knows his stuff on this.
 
Danny said:
wow this is getting technical.....
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We were asked to survey and rectify a failed system a good few years ago that had water ingress problems costing tens of thoushands worth of damage, the developer was in the process of churning out loads of tinmber framed buildings all specified with EWI so after we fixed the dodgy one we got all the forward books from the developer to fit all the EWI so I started out on the cavity system Timber frame scene really.

ironically I hate the vented systems. I do not actually believe the thermal values are up to scratch however they do protect the timber.
 
I would be keen to see/learn about it a bit more... I doubt I will ever go back on the tools but i do still find all of this interesting... possibly I am a geek....

The only rendering I ever did was sand and cement..... and even that i doubt I was doing it right as I dont think the 2 spreads that taught me had a clue what they were doing either...lol
 
plasterjfe said:
you can'i like coz all timber subframes have to have a cleared ventilated cavity continuous of a min (20 or 25mm cant remember exactly). The whole reason behind it is to protect the frame for a period of time to allow building regs such as insurance/nhbc/mortgage etc. they started out direct fitting systems in the first place only to discover a heap of failed frames rotting away due to water tracing/tracking because of closed contact with the facades so they banned the use (except for sheds and the like)
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These direct fixed insulation systems only fail due to water ingress from leading edges, soffits,reveals etc and incorrectly fitted trims.

The whole cavity rail scenario in the UK is a result of failed timber frame systems in the US, caused by not fitting the system as instructed.

The NHBC got a wiff of this and stipulate now cavity rail as standard, though the cavity will do fu*ck all to protect the timber frame if all ingress points are not sorted.

Also to note is the fact there is no code or requirement for cavity rail for timber frame refurb work or private domestic new builds. The only requirement is the use of a breathable insulation(phenolic) on barrier paper/membranes, this ensures that the Dew point is moved to the point of the render where it ought to be.

Thousands of BISF homes have been done this way and will contine to be, making an non mortgagable property mortgable.

Just my 2pennyworth!
 
22jasper said:
These direct fixed insulation systems only fail due to water ingress from leading edges, soffits,reveals etc and incorrectly fitted trims.

The whole cavity rail scenario in the UK is a result of failed timber frame systems in the US, caused by not fitting the system as instructed.

The NHBC got a wiff of this and stipulate now cavity rail as standard, though the cavity will do fu*ck all to protect the timber frame if all ingress points are not sorted.

Also to note is the fact there is no code or requirement for cavity rail for timber frame refurb work or private domestic new builds. The only requirement is the use of a breathable insulation(phenolic) on barrier paper/membranes, this ensures that the Dew point is moved to the point of the render where it ought to be.

Thousands of BISF homes have been done this way and will contine to be, making an non mortgagable property mortgable.

Just my 2pennyworth!
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totally agree the reason for failure in the first place was poorly installed systems.

the cavity systems allow for ingress although there shouldnt be any - they allow water to drain out also. the vented cavity ensures the frame stays dry and in case it does get wet can dry out again in reasonable time.

the rail systems are much trickier to install where any openings or penetrations/terminations occur as you know Jasper, all cavities must be closed and sealed off properly before any rendering can take place, fire breaks on carriers are also an extra to a standard fit system.

I recon anyone who does an approved appy course must be shown how to fit these systems as a priority over direct or bonded because if you get these wrong the building is fooked. I havnt come across many who firms who's lads fit these systems properly hence why the cavity will remain for a while yet.

of course there is no prohibition on fitting direct fix system to a steel framed building, there is no risk of the frame rotting as it is steel with cemboard racking and the warranty/nhbc/mortgage will not be affected. and obviously fixing to masonry sub-structure is fine using direct fix also.

problem is steel price, many opt for timber just to save money but fitting onto it can be a pain when you have to use packers to fix your rails onto that could be different every 250mm apart cos of the warping in the frame/sheething total nightmare when you need to maintain the cavity depth but also want a flat wall on the outside.

Just glad I got a pump, much less to worry about with mortar
 
plasterjfe said:
totally agree the reason for failure in the first place was poorly installed systems.

the cavity systems allow for ingress although there shouldnt be any - they allow water to drain out also. the vented cavity ensures the frame stays dry and in case it does get wet can dry out again in reasonable time.

the rail systems are much trickier to install where any openings or penetrations/terminations occur as you know Jasper, all cavities must be closed and sealed off properly before any rendering can take place, fire breaks on carriers are also an extra to a standard fit system.

I recon anyone who does an approved appy course must be shown how to fit these systems as a priority over direct or bonded because if you get these wrong the building is fooked. I havnt come across many who firms who's lads fit these systems properly hence why the cavity will remain for a while yet.

of course there is no prohibition on fitting direct fix system to a steel framed building, there is no risk of the frame rotting as it is steel with cemboard racking and the warranty/nhbc/mortgage will not be affected. and obviously fixing to masonry sub-structure is fine using direct fix also.

problem is steel price, many opt for timber just to save money but fitting onto it can be a pain when you have to use packers to fix your rails onto that could be different every 250mm apart cos of the warping in the frame/sheething total nightmare when you need to maintain the cavity depth but also want a flat wall on the outside.

Just glad I got a pump, much less to worry about with mortar
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Lol crist sounds like a compltely different trade to plastering....
 
s.p.t plastering said:
Lol crist sounds like a compltely different trade to plastering....
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We use a mix of fixers and renderers for the rail system mainly, not spreds. most big firms try to get labourers now or EU to fix the insulation then trowel trades to finish off. looking upon fixing the insulation as a lesser trade is where most of the problems begin I recon.
There is a massive job on housing on the go right now and the gangs of EU have been employed to fit the boards at crazy low rates but the EU boys are walking away (we all know they dont really work for less money) the firm have underestimated the value of it and tried to cut cost. put it this way I wouldnt want them working on my house coz the boards are not being fixed properly, hence the cycle begins all over, quick and cheap is what they want in britain - no room for quuality
 
F**k me you need a brain like steven hawking to be a spread these days.........Thats me knackered think al re-train to rocket scientist.............:RpS_laugh:
 
plasterjfe said:
We use a mix of fixers and renderers for the rail system mainly, not spreds. most big firms try to get labourers now or EU to fix the insulation then trowel trades to finish off. looking upon fixing the insulation as a lesser trade is where most of the problems begin I recon.
There is a massive job on housing on the go right now and the gangs of EU have been employed to fit the boards at crazy low rates but the EU boys are walking away (we all know they dont really work for less money) the firm have underestimated the value of it and tried to cut cost. put it this way I wouldnt want them working on my house coz the boards are not being fixed properly, hence the cycle begins all over, quick and cheap is what they want in britain - no room for quuality
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Bang on there,mate

Quality application of any insulated system is paramount these days.

I know guys that are applying 140mm Phenolic for £2.75 pm2 direct to masonry. Peanuts really.The attitude is slap it up poorly and let the renderers take care of all the bumps with 8mm thin coat work!

Flat walls start with the insulation, but you rarely get them at those rates.
 
It is true that the modern rendering market is getting technical. Probably too technical for the average spread. I can see the joiners doing the fixing of the rail systems and cement boards and leaving the wet part of it to us.

You have this Scottish company going around signing anybody up for NVQ2 in EWI systems and we all know it means F, all. I got my Labrador an NVQ2 in plastering last year and all he had to do to pass was have his photo taken troweling up some S&C and skimming. Never touched plaster in his life! I am more for the manufacturers training people up and only their approved applicators can use their products.

Lets see what happens when the Green deal gets underway.
 
22jasper said:
Bang on there,mate

Quality application of any insulated system is paramount these days.

I know guys that are applying 140mm Phenolic for £2.75 pm2 direct to masonry. Peanuts really.The attitude is slap it up poorly and let the renderers take care of all the bumps with 8mm thin coat work!

Flat walls start with the insulation, but you rarely get them at those rates.
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sh1te rates them, utter sh1te.

there is one basecoat on the market that goes on no more than 2-3mm thick, wonder how you go on over pi55ed walls with that
 
To insulate plywood there are many ways. like: vaccum the plywood from dust wip it with tack cloth. measure the each plywood, press the insulation sheet to plywood there are many ways to do it but i will come with full detail
 
plasterjfe said:
you can'i like coz all timber subframes have to have a cleared ventilated cavity continuous of a min (20 or 25mm cant remember exactly).
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Ok i Know nothing about this so i'm asking how the rails are installed if the cavity has to be continuous surely the rail stops the continuous flow ?
 
KevRM said:
Ok i Know nothing about this so i'm asking how the rails are installed if the cavity has to be continuous surely the rail stops the continuous flow ?
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No mate. The rails are perforated the air flow is vertical so vertical fixing onto battens is also allowwd on some systems.

The cavity must be able to drain free any moisture that might ingress. Although it should not get in their in the first place imo
 
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