Observatory Insulation / breathable membrane ??

[Skipper Billy]

I have finished the frame for my micro observatory.  

 

 

The frame is made from 2” x 2” timber and I am about to clad it with 19mm weatherboarding.

 

My question is – should I use any sort of membrane between the frame and the weatherboarding?

 

And/Or insulation or lining inside ?

 

It’s a concrete base if that makes any difference? It will have thermostatically controlled background heating and a dessicant dehumidifier installed.

 

Any help, suggestions or guidance most welcome!!

 

[Astroboffin]

I would, but put some vents in the sides top and bottom though, to get a really good airflow, which will stop any condensation or damp, many people build obsy''s and insulate and put heat in, then they get full of damp from condensation, because of no ventilation.

ventilation is the key to no damp, if you need a dehumidifier then you have damp, which means not enough ventilation, so ventilate then no need for heat or dehumidifier.

but still a good idea to put a waterproof membrane between the outer skin and frame, but a breathable one.

AB

[Bizibilder]

My wooden obs has a breathable membrane under the outer cladding.  The frame is 3x2 timber and inside of the frame is lined with 3mm ply - I suppose the trapped air provides a little insulation maybe?  There is quite a gap (2-3 cm) round 3 sides of the roll off roof that provides plenty of ventilation.  I have no problem with damp/humidity at all. 

[101nut]

It's easy and cheap to put membrane on before you clad. It stops any water ingress if you have get knot-hole or whatever in the boarding.

 

AndyG

[Skipper Billy]

Thanks guys - sounds like a waterproof but breathable membrane behind the cladding is the way to go.

Now if I can just find somewhere that sells less than 50 - 100 metre rolls ...........

[Physopto]

Check out a builder for offcuts. Up there in Bonny Scotland a lot of the houses are timber clad and they will surely have offcuts left over.

Derek

[Bizibilder]

This is the stuff I used:  http://www.screwfix.com/p/ybs-roofers-choice-roofers-002-light-breathable-membrane-grey-1mm-x-25m/21912#

[Skipper Billy]

Most houses around here are timber framed and after a bit of sweet talking (and the promise of a bottle of whisky!) a local builder is letting me have enough roll ends to do the job.  Happy days!

Thanks everyone for your help.

[Physopto]

Which whiskey? Malt or blend? Important questions you know!   

 

[Skipper Billy]

Caol Isla - a tasty single malt from just down the road! 

[Physopto]

Well you paid the man handsomely. Cracking malt. ?

[Tinker1947]

My out walls are wood with a breathable membrane behind the wood, the gap is 2" the inner wall is sterling board, in the floor and the top of the gap i put in some ventilation with these, just drill the right size hole and knock them in....