Hi,
I've stumbled across this site quite a lot whilst researching for my garden log cabin, however I'm now stumped and need to ask for some help, which should be relatively straight forward.
I've got a 4mx4m log cabin, it is constructed of 45mm dual T&G timber, it has a 100mm concrete base, the building itself sits on 70mm pressure treated bearers, it has a pitched roof with a central ridge of 2.4m, wall are 2m high and the roof is finished with shingle.
So far I've battened the floor and walls out to 45mm, installed 40mm Celotex between them and layed Treated T&G chipboard flooring. The walls have a breathable membrane on the cold side of the insulation and behind the timbers and both floor/walls have a Polythene dampness barrier on the warm side. The walls will be finished with Ply.
Ok, so far so good, I've also decided to go with a roof cavity as advised by Celotex when enquiring about the insulation, to that end I've left a 95mm gap all the way around the walls from the ceiling with the intention of using DPM, 40mm insulation, breather membrane and then the 55mm gap between that lot and the original ceiling.
I'm having a 6 way consumer unit feeding off of a fresh supply from the house consumer unit with armoour cable in a trench. I was then intending on having a oil filled radiator/tube heater and dehumidifier/air conditioner.
My problem is now this, I cannot for the life of me find a tidy way of venting this air space, due to the purlings, I have 4 isolated runs from front to back which will need venting to the outside world to ensure I dont end up with a rotting ceiling, all I can find online are 70mm soffit vents.
Is there something I can make up?
Do I actually need to cut long slots or round holes or can I not just drill lots of 1cm holes and cover them with a mesh and some kind of wooden frame?
Also is there a calculation I can use to work out what size vents I need for the air space? (each run is 4m long and either 1.2m or 0.8m wide and obviously 55mm deep).
Further to this, I'm unsure how to finish the breather membrane on the walls, do I allow it to pertrude into the ceiling cavity to "breath" to atmosphere or isn't this how it works.
I'm 90% finished on this project so any help for these final items most appreciated.
FYI its to be a model plane workshop, I fly model planes and just moved to petrol ones so need to get them out of the house as they're larger and petrol smells a whole lot more than glow fuel.
I've stumbled across this site quite a lot whilst researching for my garden log cabin, however I'm now stumped and need to ask for some help, which should be relatively straight forward.
I've got a 4mx4m log cabin, it is constructed of 45mm dual T&G timber, it has a 100mm concrete base, the building itself sits on 70mm pressure treated bearers, it has a pitched roof with a central ridge of 2.4m, wall are 2m high and the roof is finished with shingle.
So far I've battened the floor and walls out to 45mm, installed 40mm Celotex between them and layed Treated T&G chipboard flooring. The walls have a breathable membrane on the cold side of the insulation and behind the timbers and both floor/walls have a Polythene dampness barrier on the warm side. The walls will be finished with Ply.
Ok, so far so good, I've also decided to go with a roof cavity as advised by Celotex when enquiring about the insulation, to that end I've left a 95mm gap all the way around the walls from the ceiling with the intention of using DPM, 40mm insulation, breather membrane and then the 55mm gap between that lot and the original ceiling.
I'm having a 6 way consumer unit feeding off of a fresh supply from the house consumer unit with armoour cable in a trench. I was then intending on having a oil filled radiator/tube heater and dehumidifier/air conditioner.
My problem is now this, I cannot for the life of me find a tidy way of venting this air space, due to the purlings, I have 4 isolated runs from front to back which will need venting to the outside world to ensure I dont end up with a rotting ceiling, all I can find online are 70mm soffit vents.
Is there something I can make up?
Do I actually need to cut long slots or round holes or can I not just drill lots of 1cm holes and cover them with a mesh and some kind of wooden frame?
Also is there a calculation I can use to work out what size vents I need for the air space? (each run is 4m long and either 1.2m or 0.8m wide and obviously 55mm deep).
Further to this, I'm unsure how to finish the breather membrane on the walls, do I allow it to pertrude into the ceiling cavity to "breath" to atmosphere or isn't this how it works.
I'm 90% finished on this project so any help for these final items most appreciated.
FYI its to be a model plane workshop, I fly model planes and just moved to petrol ones so need to get them out of the house as they're larger and petrol smells a whole lot more than glow fuel.
