shed insulation

[Richard_A]

First of all sorry about posting this as I know it's been done before but I would just like to canvas opinion.

 

I am going to have the use of a 9' 6" x 4' 6" stone outbuilding for my hobbies, it's just a bit cold.

 

It has a stone slate roof which has a membrane between the slates and roof joists which are 4" thick, so I was thinking about fitting some 25mm insulation between the joists and plasterboarding it.

 

It's the walls I'm unsure about, I was thinking about battening it out by 25 mm and filling the gaps with 25mm insulation and plasterboarding this, but I'm not sure if I need to leave an air gap between the layers?

 

For the electrics, I was thinking about buying some armoured cable and having a permenant "extension" fixed to walls at high level, and fed into the house, where i can fit a plug on it.( I live in a rented house and doubt my landlady would allow me(using an electrician)to have a permenant feed via fuse board)

 

Any opinions/help appreiciated.

[BG John]

As I understand it, drylining stone walls in houses isn't recommended any more. I think that research has shown that the plasterboard can rot in time. From my experience, I've removed uninsulated plasterboard on 25mm battens from a lime plastered upstairs wall in my house, and the wall was damp. This was in an unfinished and unheated part of the house, so probably not too different to a well built shed. Any insulation would have been damp too. The outside wall is cement rendered, and so wasn't breathing. From everything I've learned, breathable materials are the safest option.

[Richard_A]

so possibly it would be better to use something like plywood to line it out with instead of plasterboard?

[BRealistic]

Can't comment on the treatment of the walls, but if the roof has 4" rafters... why not fill the gaps with insulation the same thickness ie. 100mm in today's money. Every little helps, we're told!

 

EDIT

(After what follows, I shouldn't have commented on the roof insulation either!!!!)

[Richard_A]

I can get my hands on some 25mm stuff for nowt!

[AndrewC]

Just a suggestion. You should consider 50mm for the wall insulation, and as mentioned above go for 100mm in the roof if you've got 4" rafters. Plasterboard isn't a problem as long as you put a damp proof membrane between the wall & insulation.

 

 

Edit: then double up on the 25mm insulation if you can get enough.

[Richard_A]

Just a suggestion. You should consider 50mm for the wall insulation, and as mentioned above go for 100mm in the roof if you've got 4" rafters. Plasterboard isn't a problem as long as you put a damp proof membrane between the wall & insulation.

 

 

Edit: then double up on the 25mm insulation if you can get enough.

do you mean like this?

 

http://www.diy.com/nav/build/building-materials/damp-proof-courses-membranes/damp_proof_membranes/NDC-Vapour-Barrier-Roll-Green-9707871?skuId=10078608

[nigeln]

Living in the dampest country in the world where it`s only fine between the showers   They use a process called tanking on old buildings, which is a coat of thick black mastic painted in the inside walls before any drylining is carried out. We can buy plaster boards with 50mm insulation or foil coated plaster board here but not too sure what`s available in the uk.

With the roof I would go for 50mm styrne sheets 8`x4` there light  weight,good insulation and don`t need painting.

[chris p bacon]

Apart from the insulation the second most important is Ventilation.

 

For the roof, if your joists are 100mm then the max insulation is 75mm with a 25mm airspace from the top of the insulation to the underside of the roofing felt/membrane.

 

For the walls you can build a secondary stud wall that is just bracketed to the outside wall and again leave an airspace between the insulation and wall.

 

As for damp, does the outbuilding have a suitable (and working) damp proof course ?

 

What is the floor like ? could be as it is an outbuilding it is just tiles laid on dirt.

 

If either of the above apply then I'm not so sure about paying good money as it will have little effect, also if the house is rented you will be paying to improve someone elses property.

 

Instead of the above why not build a half decent shed ? you could take it with you if you move, just a thought.

[jcm@gwr]

IMHO, do not use 100mm with 4" roof joists, you will not allow the wood

to 'breathe', and it will rot eventually, 75mm is the max.

Better still use the silvered bubble wrap (and the metal tape) and you will

have same insulating properties as 100mm polystyrene, plus it doubles

as a membrane.

You could also use it on the walls, as it will not reduce the size of the room

to much.

Jeff

 

Edit: crossed posts with Dave!

[BG John]

Living in the dampest country in the world where it`s only fine between the showers   They use a process called tanking on old buildings, which is a coat of thick black mastic painted in the inside walls before any drylining is carried out.

I suppose that's ok for a shed, but the water that gets into the wall has to go somewhere, and wet walls are colder than dry ones. My stone house in West Wales had cement covering the inside and outside of the walls for 40 years, and the walls were wet when it came off. Drylining and tanking are out in conservation building now. I suppose as it's only an outbuilding, and it's rented, it may not matter, but if I was the landlord I would insist on lime and breathable insulation. Is it listed?

[Richard_A]

no it's not listed and im not too bothered about spending abit of money on it as I envisage staying their for quite a few years.

 

turning out to be abit of a minefield this

[chris p bacon]

I suppose that's ok for a shed, but the water that gets into the wall has to go somewhere, and wet walls are colder than dry ones. My stone house in West Wales had cement covering the inside and outside of the walls for 40 years, and the walls were wet when it came off. Drylining and tanking are out in conservation building now. I suppose as it's only an outbuilding, and it's rented, it may not matter, but if I was the landlord I would insist on lime and breathable insulation. Is it listed?

Tanking is a form of vertical damp course used in basement areas or below ground.

 

Drylining is plasterboard which is dot & dabbed (glued) to a wall.

 

Both of these are acceptable in building in their required fields although neither are suitable for the OP.

 

Cement render should only be applied either below damp or above a working DPC and the 2 should not be connected. Lots of problems in older buildings stem from the 60's where render was seen as a cure for some problems which then made them worse.

[AndrewC]

do you mean like this?

 

http://www.diy.com/nav/build/building-materials/damp-proof-courses-membranes/damp_proof_membranes/NDC-Vapour-Barrier-Roll-Green-9707871?skuId=10078608

that's the stuff.

[jon_1066]

I wouldn't bother with the walls if I were you.  You will see a marked improvement with the roof insulation.  The walls will be the least of your heat losses, especially if they are solid stone.

 

Also make an effort to secondary glaze the windows to cut down drafts and fit some draft excluder to the door.

[chris p bacon]

I wouldn't bother with the walls if I were you.  You will see a marked improvement with the roof insulation.  The walls will be the least of your heat losses, especially if they are solid stone.

 

Also make an effort to secondary glaze the windows to cut down drafts and fit some draft excluder to the door.

 

Sorry but I'm afraid you are wrong there,  it's pointless secondary glazing the windows if the area around them has heat loss.

 

Any building should be seen as a whole, one of the most expensive things we buy for the home now is power, so any form of upgrade has to be spread over the whole building to gain the most from it.

 

As for stone walls not contributing to heat loss, unless they are about 4 feet thick you may as well have the windows open.

[westcountryman]

Hi,

Just a few ideas:- The poster suggesting 'tanking' is on the right track.

The inner walls need to be coated with Thompson's Water Seal ( a clear liquid, that will help damp proof & stabilise the stone walls)

Then, apply a single coating of Roof Seal ( it's a thick bitumen mastic, available from Wickes, Jewson etc) around the entire inner wall surface. Please wear gloves, it will ruin clothing!!

You can then batten out the inner face, & use foil coated closed cell insulation batts ( Kingspan, Celotex, Knauff etc), or Space Blanket ( layered insulation on a roll)

The final application should either be foil backed plasterboard, or preferably cement board, both of which resist damp.

That's the walls dealt with.

The ceiling is simple. Measure the roof joists & choose either foil coated insulation (as above) or Space Blanket ( a multi layered insulation on a roll )

Then, it's simply a case of dry lining the ceiling structure with either plasterboard or exterior ply.

Todays top tip :- Try searching e-bay for insulation products, it's much, much cheaper, or try one of the many building supplies surplus outlets online.

Just Google them, & you'll be absolutely amazed as to how much you can save on general retail prices.

I know that all of this sounds a bit involved, but, you could get this all done in a weekend.

It really is more complicated when written down as instructions, rather than just getting on with the job!

Finally, don't forget the door. For insulation & security purposes, have a word with your friendly local UPVC supplier, they often have second hand secure, plastic doors & window frames knocking about.

Hope all of this helps,

Cheers

Rob

[Happy Hippo]

Just a thought............

 

By the time you have fitted all this insulation with the corresponding gaps etc to your walls isn't the outbuilding going to be getting a bit on the narrow side?

 

My workshop is a 14 x 10 shed, but if I were going to start again, I'd opt for one of the 'log cabins' that are now popular.

 

Regards

 

Richard

[chris p bacon]

Hi,

Just a few ideas:- The poster suggesting 'tanking' is on the right track.

The inner walls need to be coated with Thompson's Water Seal ( a clear liquid, that will help damp proof & stabilise the stone walls)

Then, apply a single coating of Roof Seal ( it's a thick bitumen mastic, available from Wickes, Jewson etc) around the entire inner wall surface. Please wear gloves, it will ruin clothing!!

You can then batten out the inner face, & use foil coated closed cell insulation batts ( Kingspan, Celotex, Knauff etc), or Space Blanket ( layered insulation on a roll)

The final application should either be foil backed plasterboard, or preferably cement board, both of which resist damp.

That's the walls dealt with.

The ceiling is simple. Measure the roof joists & choose either foil coated insulation (as above) or Space Blanket ( a multi layered insulation on a roll )

Then, it's simply a case of dry lining the ceiling structure with either plasterboard or exterior ply.

Todays top tip :- Try searching e-bay for insulation products, it's much, much cheaper, or try one of the many building supplies surplus outlets online.

Just Google them, & you'll be absolutely amazed as to how much you can save on general retail prices.

I know that all of this sounds a bit involved, but, you could get this all done in a weekend.

It really is more complicated when written down as instructions, rather than just getting on with the job!

Finally, don't forget the door. For insulation & security purposes, have a word with your friendly local UPVC supplier, they often have second hand secure, plastic doors & window frames knocking about.

Hope all of this helps,

Cheers

Rob

Rob a couple of points in your post.

 

Thompsons water seal is effectively a clear seal (bit like a PVA) applied to the outside of walls to try and stop "spalling" (crumbling brickwork) frankly it stores more problems as it doesn't deal with any cause of damp just covers it up and moves it to somewhere else it can get out., Brickwork should be allowed to breathe and thses sort of products stop that happening.

With the roof seal the clue is in the name....it's a roof covering, again this is a product that has come about to cater for people that would rather cover a problem than replace, It is not designed to be subjected to constant moisture which a tanking situation can give.

 

It is better to deal with any problem of damp or ventilate rather than cover over as the problem will just get worse and show elsewhere.

 

You are correct about foil backed plasterboard etc.

 

As for cheap insulation, I have tried the various companies advertising seconds/damaged etc and everytime it's been cheaper to get some from a local merchant after ringing around for the best price. looking for another 90 square metres at the moment.

[big jim]

Should has read this before i insulated my shed!

 

Ive used 40mm kingspan therma panels to do it, ive not put a moisture barrier in between the woodwork and insulation as i was under the impression the silver backing would prevent moisture getting into the insulation

 

there is no gap between the insulation and the mdf i've used to line the shed, however up to now ive only temporarily attached the lining with a few screws in the corners and im wondering if its worth taking it out and putting some sort of moisture barrier in between the shed wall and insulation, if so what should i use?

[chris p bacon]

Should has read this before i insulated my shed!

 

Ive used 40mm kingspan therma panels to do it, ive not put a moisture barrier in between the woodwork and insulation as i was under the impression the silver backing would prevent moisture getting into the insulation

 

there is no gap between the insulation and the mdf i've used to line the shed, however up to now ive only temporarily attached the lining with a few screws in the corners and im wondering if its worth taking it out and putting some sort of moisture barrier in between the shed wall and insulation, if so what should i use?

Jim,

There should be a vent gap between the wall of the shed and the insulation, this is to stop moisture on the inside of the outside wall, crossing over to the insulation, as you are in a timber building you won't suffer with many of the problems of damp associated with brick/stone buildings, if you are able to remove the MDF and staple a vapour barrier between it and the insulation and then tape up any joints you will benefit from a reduction in draughts, but if you can't I wouldn't loose any sleep over it.

The difference between heat loss on a timber wall and a brick one is huge.

[big jim]

Thanks for that, the insulation is very well packed in and i've filled any gaps with offcuts etc so there is little chance of draughts getting through it was moisture i was more bothered about, the shed is a brand new one, tongue and groove type, far less chance of leaks/moisture than a lap type shed.

 

if you have a look at my thread in the layouts section (birmingham central) you can see the shed and what i have done to it, the sugesstion of a moisture barrier was also mentioned there too

[Richard_A]

cheers for the replies.

 

just checked the building again and it has a breeze block inner skin with a stone outerskin, it does have a dpc layer, but not sure about the floor unless i take a flag up.

 

It is however bone dry in there but I think part of the reason for this is there is quite a few gaps around the door and windows allowing a good airflow through it

[BG John]

just checked the building again and it has a breeze block inner skin with a stone outerskin, it does have a dpc layer, but not sure about the floor unless i take a flag up.

That makes all my comments about lime and breathable materials irrelevant then!

[chris p bacon]

cheers for the replies.

 

just checked the building again and it has a breeze block inner skin with a stone outerskin, it does have a dpc layer, but not sure about the floor unless i take a flag up.

 

It is however bone dry in there but I think part of the reason for this is there is quite a few gaps around the door and windows allowing a good airflow through it

Sounds like either fairly modern construction or a rebuild. so you should not have issues with damp.

 

maybe post a piccie ?

 

One thing I forgot, as you are renting you want to get an agreement in place before carrying out any works, even works of "improvement" can be classed as unwarranted changes and some landlords have beeen known to refuse return of bonds even though they're property has benefited. You may get on well with your landlord now but that can change very quickly.