ply sheeting a new roof advice.....

[pappasmurf]

next year we will be having a new loft conversion done to our home. i want to get the builder to "completely " remove absolutley everything of the existing roof trusses etc. as it is a 1930's semi. and we wonna start afresh.
does anyone know if after fitting new trusses, ply sheeting can be used to board up all of the new roof before battening up and tiling. i know the yanks and canadians do so in their properties.
apart from the additional weight added to the strusses are their any other disadvantages?.... i wonna do this as i am thinking of adding spray foam insulation on the inner side of the trusses and don't wonna spray directly onto the membrane/battens/tiles. and also because the plywood will give it better draught proofing and a nice plane on which to work the spray foam on. any advice will be much appreciated.

 

[freddiemercurystwin]

Totally bizarre!!! Forget the plywood complete waste of money for your location, insulate with some Kingpsan or Celotex.

 

[pappasmurf]

freddy why would you suggest that?.... you haven't given any reasoning!

 

[big-all]

you have a roof structure that is 90% up to the job
with additional support a few steels will last another few centuries
what you are actually is suggesting will possibly double the cost disruption and amount off work

 

[pappasmurf]

big-all .............. but its the draught side i'm thinking of!.... an additional few hundred quid for ply and maybe a days extra labour is what i'm thinking of!.... but the future benefits i'm sure will be of great use...don't you think?

 

[freddiemercurystwin]

No provided the insulation is properly installed it will be draught free end of story. I don't understand what benefits you think you will achieve.

 

[freddiemercurystwin]

Continuous layer of foil backed insulation running beneath the rafters all joints sealed with foil tape, where's it gonna be draughty?

 

[big-all]

big-all .............. but its the draught side i'm thinking of!.... an additional few hundred quid for ply and maybe a days extra labour is what i'm thinking of!.... but the future benefits i'm sure will be of great use...don't you think?

ok can i suggest you look at it from a different angle
your method in my experience is only an expensive choice
think off it as you have a family car without a sun roof
your choices are to fit a sun roof at say £300
or buy a new car with a sun roof already fitted for 1k
ok the old car will only be 98.7 efficient at the task where as the new car will be 99.3 with maybe 3% more room in the conversion

in other words not good value

 

[scottishslater]

Sheeting a roof before slating or tiling is pretty much the done thing in Scotland. it will be more secure when you get broken tiles etc you wont see daylight coming in you wont get ceilings coming down due to broken tiles, over all your roof will be more secure

 

[freddiemercurystwin]

Sheeting a roof before slating or tiling is pretty much the done thing in Scotland. it will be more secure when you get broken tiles etc you wont see daylight coming in you wont get ceilings coming down due to broken tiles, over all your roof will be more secure

How often does this happen in the south east, its more common the further north you go due to typically worse weather conditions. Its overkill in the south east.

 

[JohnD]

I use an industrial unit where the workshop has Kingspan on top of the (cut) roof timbers.

I thought it was a pretty good idea.

 

[catlad]

If its a detached house thats an option and it will do the same as ply.