Insulating and powering a new shed.

[peach james]

1 minute ago, Damo666 said:

Do you mean Tyvek?

 

 

One's for pants, the other for houses... there are times !

 

 

 

James

[big jim]

10 minutes ago, Damo666 said:

Do you mean Tyvek?

 

To the OP: Certainly what is needed is a Vapour Barrier on the inside and a Breathable Membrane (eg: Tyvek) on the outer side. This is so that any moisture that manages to migrate into the insulation has a chance of escaping out, and not get trapped within the construction.

 

Two points of note:

1. If moisture cannot escape it will condense within the wall construction (be that insulation, timber, blockwork). This is called Interstitial Condensation. Not good (having water form within the wall)!

2. No matter how well you install the internal Vapour Barrier, moisture will almost certainly pass through. Unless you are capable of exceptional construction by sealing all joints in the vapour barrier, along the floor junction and roof junction, make no penetrations (eg, for a wall socket, external light, TV aerial cable, shelving screw hole..... etc)

 

 I used tyvek on the internal framing of my garage build....

 

 

insulation in front of that with an air gap between then plasterboard on top 

 

Going back to the wooden shed I did in 2013....

 

Kingspan in between the rafters, probably should have used tyvek too

 

 

Then boarded over that with ply

 

never had an issue with damp other than where some of the roof felt came off and let water in

 

[Mike Bellamy]

 

Typar / Tyvek . . . . . . . 

 

Typar here

http://www.typar.com/

 

Tyvek Here

http://www.dupont.co.uk/products-and-services/fabrics-fibers-nonwovens/protective-fabrics/brands/tyvek.html

 

See here for a comparison between the two

http://www.dupont.com/content/dam/assets/products-and-services/construction-materials/assets/Tyvek-vs-Typar-Building-Science-Bulletin-K05039.pdf

 

 

[TheQ]

10 hours ago, peach james said:

 

One's for pants, the other for houses... there are times !

 

 

 

James

Tyvek does get used for other things...

 

 

[Damo666]

1 hour ago, Mike Bellamy said:

 

Typar / Tyvek . . . . . . . 

 

Typar here

http://www.typar.com/

 

Tyvek Here

http://www.dupont.co.uk/products-and-services/fabrics-fibers-nonwovens/protective-fabrics/brands/tyvek.html

Typar seems to be a North America product.

Assuming the OP is UK (or EU) based, then Tyvek is the product they should be looking at (although there are other manufacturers with similar Vapour Barrier products available).

[Ian Morgan]

Slight change of subject, but seeing an interior view of your new shed on another thread, it looks like the bars on your windows might be too far apart. There is a safe maximum separation, to avoid children getting their heads stuck. I cannot find a definitive answer, but I think I had to space bars at no more than 4 inches apart on a vulnerable back door window where I used to live.

 

[Quarryscapes]

Very interested in this topic as I am building a Shed as a lean-to extension of my kitchen which will become a workshop. The shed is pretty standard T&G cladding over essentially a 2x1 frame. Thinking of 30mm PIR board flush with inner lining (ply) as insulation. Would this require an extra membrane anywhere, and would you do anything different regarding the wall that will be butted up against the house? 

 

How about the floor? Again it's T&G boards over 2x1 joists. Was thinking of laying the joists on plastic runners sat on concrete slab, with PIR board again stuck to the floor and air gap between bottom of PIR and concrete, all boxed in to keep the creepy crawlies out. Seem sensible?

 

Does it make a difference if air gap is to the inside or outside?

Edited April 15, 2019 by Quarryscapes

[Richard_A]

Check the planning portal for approved documents regarding insulation and general construction details, they have all the correct information in them and include references to British standard documents which are also a very good guide on what you need to do.

[TEAMYAKIMA]

Ok …. am starting the work tomorrow. 

 

I have gone with Celotex 50mm entirely. And 18mm moisture proof plasterboard. 

 

What I don't understand is that people are still telling me that I need a moisture proof membrane . If the Celotex is waterproof and the plaster board is moisture proof , why the membrane - thoughts?

 

Also some people have said cut the membrane and hag it vertically between the uprights, whilst others have said lay it horizontally right along the walls including over the uprights - which is correct?

 

Paul

[Damo666]

4 hours ago, TEAMYAKIMA said:

Ok …. am starting the work tomorrow. 

 

I have gone with Celotex 50mm entirely. And 18mm moisture proof plasterboard. 

 

What I don't understand is that people are still telling me that I need a moisture proof membrane . If the Celotex is waterproof and the plaster board is moisture proof , why the membrane - thoughts?

 

Also some people have said cut the membrane and hag it vertically between the uprights, whilst others have said lay it horizontally right along the walls including over the uprights - which is correct?

 

Paul

[Thought I replied via my phone earlier, now I see that it wasn't posted. Here it goes again. See if I can remember what I wrote.]

 

It's not a 'Moisture Proof Membrane' that you need, its a 'Vapour Barrier'.

Also, whilst on terminology, it's Moisture RESISTANT Plasterboard, not moisture proof.

 

Celotex won't prevent moisture from passing through its joints. Even with T&G insulation, moisture will always find it's way from the high temp side to the low temp side.

 

Moisture resistant plasterboard is ideal for bathrooms and kitchens, areas with a high degree of humidity. As I said above, it's not a barrier (not moisture proof). I don't think you need it in your hobby room, unless you are generating lots of moisture.

FYI: Moisture (water) on ordinary plasterboard will cause the paper face to disintegrate. Believe it or not, it's the paper that gives plasterboard its strength (which is why, when screw fixing, you are only supposed to have the screw head press into the surface and not tear the paper).

 

You need to prevent moisture laden air from passing from the warm side (your train room) to the cold side where it will condense if the dew-point is somewhere within the wall structure (this is a technical calculation based on various temperature scenarios). A Vapour Barrier (VP) on the inside will help prevent moisture from entering the wall fabric.

 

A VP laid vertically will allow you to seal it along the joints (ie: the laps) over the studs. If you lay it horizontally, you will have difficulty in sealing the VP joints / laps between the studs where there is no support.

 

HTH.

Edited April 17, 2019 by Damo666
Typos

[Richard_A]

A  vapour control layer is to help keep intersitsial condensation in check. Warm air can hold quite a lot of moisture in it i.e it has a high relative humidity, when the warm air moves through a buildings fabric and comes into contact a cooler surface it then cools down and the water condensates, which if there is no means of escape for the water via drainage or enough ventilation to drive the moisture out, it can be extremely detrimental to the fabric of the building.

[TEAMYAKIMA]

5 hours ago, Damo666 said:

 

It's not a 'Moisture Proof Membrane' that you need, its a 'Vapour Barrier'.

 

Celotex won't prevent moisture from passing through its joints. Even with T&G insulation, moisture will always find it's way from the high temp side to the low temp side.

 

You need to prevent moisture laden air from passing from the warm side (your train room) to the cold side where it will condense if the dew-point is somewhere within the wall structure (this is a technical calculation based on various temperature scenarios). A Vapour Barrier (VP) on the inside will help prevent moisture from entering the wall fabric.

 

A VP laid vertically will allow you to seal it along the joints (ie: the laps) over the studs. If you lay it horizontally, you will have difficulty in sealing the VP joints / laps between the studs where there is no support.

 

HTH.

 

Hello again

 

Thank you for your continued interest in my problem.

 

On the advice of the shed manufacturer (CRANE GARDEN BUILDINGS)  I have bought IRKO BREATHABLE MEMBRANE  - is that a VP?

 

Are you saying that I need to seal around the edges of the VP with tape or similar - I was just going to staple it to the frame.

 

Paul

[Richard_A]

A breathable membrane is not a vapour control layer. A vapour control layer is basically a plastic sheet or foil backed plasterboard.

[Damo666]

1 hour ago, TEAMYAKIMA said:

 

Hello again

 

Thank you for your continued interest in my problem.

 

On the advice of the shed manufacturer (CRANE GARDEN BUILDINGS)  I have bought IRKO BREATHABLE MEMBRANE  - is that a VP?

 

Are you saying that I need to seal around the edges of the VP with tape or similar - I was just going to staple it to the frame.

 

Paul

As RKA said, a breathable membrane is not a vapour barrier membrane. The name is a bit of a clue, (breather and barrier, the words I've used).

 

With due respect to RKA, a good Vapour Barrier is more than a plastic sheet. Plastic tears easily. Plastic can degrade with heat, UV light and sometimes if in contact with cement. Even Visqueen isn't a proper vapour barrier unless it's encapsulated under a concrete screed. Certainly not hung vertically. Again, it will tear.

 

The best type of vapour barrier will have a geotextile membrane woven into it, to reinforce it so that it won't tear.

See here for information. I've used this company's product a few times. Monarflex 275

 

The breathable membrane is for (if) any moisture does get past your vapour barrier, so its not trapped inside to do lots of damage, its to give the moisture a chance to get out. But do not solely rely on this as a suitable building solution, you must have a vapour barrier too.

 

Vapour barrier to the inside

Breathable membrane to the outside

[Richard_A]

I didn't know about VCL with a geotextile incorporated, all the ones I've used are a 300 gauge (if I remember correctly) translucent plastic sheet, thanks for the information on this as I'm thinking of a shed for myself at some point and I wouldn't have thought of one.

[TEAMYAKIMA]

As the OP, thanks to everyone for posting.

 

I am starting the work in 15 minutes  - I will report back in 20 years to tell you all how it turned out.

 

 

Edited April 18, 2019 by TEAMYAKIMA

[Enterprisingwestern]

 

As I've mentioned previously on various shed builders threads, IMHO a heat recovery ventilation system is a must in "sealed" wooden sheds, you'd be amazed at the amount of water vapour just breathing produces, unless you're thinking of holding your breath whilst in there!

 

Mike.