Shed insulation advice needed

[Mc9]

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1. 

   Mc9New Member

   Hi all. I hope it's ok to ask these questions here.

   I'm getting a 18' x 8' shed in my garden and I just wanted to see if I could get some advice on insulation.
   
   It's a T&G shed and will be built on flat level concrete paving.
   It will have 50mm x 75mm framing and I'll be using 50mm PIR (cellotex maybe) leaving a 25mm air gap. Over the top of that I will use ply or plasterboard, not sure what's best or cheapest. I will probably do the same on the roof or will that a bigger air gap?
   
   I have had a smaller shed off this company before and is decent quality. It has a T&G floor and sits on 50mm x 50mm batons to keep it off the floor.
   I was thinking of putting 50mm batons on the floor then putting 25mm cellotex down with 25mm air gap. Or would it be better to use 50mm cellotex with no airgap? I think if I used 75mm batons the floor will be to high. I would then put ply or something similar over it. Again, does this sound ok?
   
   Also can anyone recommend the best place to buy 50mm PIR board like cellotex or similar? Prices seem to vary wildy from £20/25 to £40 for 2440 x 1220.
   
   It will be used as a games room so I want to do a good job of it if I can. I am planning to use a dehumidifier running as much as needed to keep control of moisture.

   Thanks for reading and any help is greatly appreciated.

[Mc9]

Hi, sorry I know these are probably silly questions and pretty basic but I've seen different answers given and I just wanted to get some expert opinions so I know what to do for the best. Thanks 

[ProDave]

I am not sure I would be too bothered with air gaps. I would just fill the entire frame width with as much insulation as you can fit, tape and / or foam all the joints 

[Onoff]

 

I'd advise against insulating a shed using cans of expanding foam. Like a poor man's Icynene.

[Ferdinand]

@Mc9

 

Welcome.

 

1 - Looks like you need 20 sheets approx. 4 x 4 for the walls floor roof, plus 2 x 2 for the ends. Minus holes so they can get in and see out.

2 - I see that Seconds and Co have non-foiled 60mm pir at 12.60 a sheet at present. 

https://www.secondsandco.co.uk/sale

3 - I would consider making the shed a little bit shorter to match 2 sheets in length if poss.

4 - For the walls have a look at the hollow plastic ship lap. Comes in 5m lengths so just need to handle one length and would work out at about 5 per sqm . Far more robust than plasterboard when it leaks.

5 - Have a look at roofing laths for your floor battens. Protected, cheap and come in 25mm x 50mm.

 

F

 

* Are you one of these annoying people who got all the three letter internet domains ? ?

Edited July 6, 2019 by Ferdinand

[Mc9]

Thanks guys I really appreciate the replys, that's given me more to think a out.

 

I never thought about hollow plastic ship lap, that would mean I could get get a couloured ship lap and not worry about painting. Although I do want to keep the shed at 18' wide so I'd need a join as 5m is just over 16'.

 

That leads to another question. Does it not really matter what material you line the inner walls/floor/ceiling regarding insulation benifits?In other words, once I've fully insulated and put foil tape over joints etc is it just a matter of using whatever material I prefer as it won't really help insulation further if it's ply/plasterboard/plastic etc?

 

What about the air gap then. Obviously this is just essentially a shed but I've read so many people saying you must have an air gap then other people say it will be ok so I'm a bit confused. I'm going to keep some arcade machines in there so want it done as well as I can and keep on top od moisture with the help od a good dehumidifier to protect the electronics.

I've read you definitively need a decent air gap in the roof particularly but does it really not matter to much if I don't have one in the walls or floor?

Even though it's much more expensive I will go for the foil faced PIR but thanks for the link Ferdinand and no I don't have any 3 letter internet domains

 

 

 

 

 

 

[Ferdinand]

Suspect that once you start comparing prices you may decide you like White as a background for posters. Best of luck.

 

Shiplap will also provide you with a potential effective 2nd barrier to water vapour.

 

Ferdinand

 

[Mc9]

Can anyone recommend a good place to get plastic shiplap if I decide to use this internally over the top of the insulation? I've had a look and there are a lot of places selling it but I don't know if some are better quality than others or if some are more fire resistant than others and safe around electris etc?

 

Also does anybody know if plastic shiplap would me more or less likely to attract condensation?

[Ferdinand]

.
 

Edited July 8, 2019 by Ferdinand

[PeterW]

Plastic will be less likely to cause condensation unless you are creating a lot of steam in the shed ..????

 

You will be better off finding a local supplier as shipping on 5m lengths will be horrendous, and short lengths will be charged at a premium. 

 

Fire retardant plastic will will be a problem unless you go for an ABS based product. Why the requirement ..??

[Ferdinand]

1 hour ago, PeterW said:

Fire retardant plastic will will be a problem unless you go for an ABS based product. Why the requirement ..??

 

Good point.

 

I think I will check that with local BCO wrt UPVC based products, and their use in internal spaces.

 

F

Edited July 8, 2019 by Ferdinand

[Ferdinand]

On 06/07/2019 at 07:55, Ferdinand said:

4 - For the walls have a look at the hollow plastic ship lap. Comes in 5m lengths so just need to handle one length and would work out at about 5 per sqm . Far more robust than plasterboard when it leaks.

 

@Mc9

 

Further to this, you need to make sure that the product you select is the correct one wrt H&S etc. There are products designed for external and internal use; make sure you use something suitable should you choose to do so. Check it.

 

(Thanks @PeterW)

 

Ferdinand

 

Edited July 8, 2019 by Ferdinand

[Mc9]

Thanks for the replys guy's.

 

Hi @PeterW The reason I was asking how resistant these plastics may be to fire is there will be quite a few arcade machines in there so I guess there would be more potential for something going wrong with old electronics like a spark from a dodgy crt etc. I just don't want to do anything daft and all this isn't my area of expertise.

 

No I won't be generating any steam etc I was just wondering if condensation may be more likely to form on plastic than ply or mdf etc once the temperature goes from warm to cold at night. Having said that, I am planning to use a dehumidifier as much as needed in there and will no doubt be asking questions doon about ventilation in the appropriate section on here.

 

Thanks @Ferdinand I will look further into shiplap in more detail as recommended. I shouldn't need to decide for 2 or 3 weeks yet but I'm sure I'll think of other silly questions to ask in the meantime

[Mc9]

Hi guys. Had loads of hold ups but I'm finally going to start insulating tomorrow starting with the floor and I've got a quick question.

 

It's a tounge and groove floor and I have a 63mm timber frame on top. Question is, do I put my 50mm cellotex in touching the floor or do I leave a 13mm air gap between the floor and the cellotex. What would be most effective?