partially insulating a shed

[jonnyuk]

hi all, after some advice on partially insulating a shed. its 10x8 shiplap clad with pitched roof. the ground work is a weed matt, then plastic base with pea gravel in the honey comb, the shed base is 3  wooden batons, on top of this is single sheet of wood with a shiplap base on top of that. Roof is just wooden sheets with felt over the top.

 

my plan is to floor the shed with office carpet tiles (ones with a plastic back), the roof i plan use some sort of insulation titles, with a water barrier. I plan to to vent near the eves to create airflow above the insulation tiles. I may also vent just below the water barrier to allow hot air to escape. i really dont want to insulate the walls.

 

I have a two window pains that i plan to insulate with perspex on the inside to create an air cavate. 

 

how does this sound? i've read so much on this topic and watched so many you tube video's my head is in a spin, don't know what to do for the best.

I could just add vents near the roof line and leave it at that, yes it will be cold in the winter but i can live with that, its more the summer, the shed is already red hot and we are not in the peak of summer yet. i can't imagine that heat is good for model trains!

thanks

 

 

[Andymsa]

28 minutes ago, jonnyuk said:

hi all, after some advice on partially insulating a shed. its 10x8 shiplap clad with pitched roof. the ground work is a weed matt, then plastic base with pea gravel in the honey comb, the shed base is 3  wooden batons, on top of this is single sheet of wood with a shiplap base on top of that. Roof is just wooden sheets with felt over the top.

 

my plan is to floor the shed with office carpet tiles (ones with a plastic back), the roof i plan use some sort of insulation titles, with a water barrier. I plan to to vent near the eves to create airflow above the insulation tiles. I may also vent just below the water barrier to allow hot air to escape. i really dont want to insulate the walls.

 

I have a two window pains that i plan to insulate with perspex on the inside to create an air cavate. 

 

how does this sound? i've read so much on this topic and watched so many you tube video's my head is in a spin, don't know what to do for the best.

I could just add vents near the roof line and leave it at that, yes it will be cold in the winter but i can live with that, its more the summer, the shed is already red hot and we are not in the peak of summer yet. i can't imagine that heat is good for model trains!

thanks

 

 

 

I have to ask what benefit partly insulating the shed would achieve apart from the wasted cost of insulation. But if you did decide to fully insulate don’t forget a vapour barrier.

 

i would try to get any wood off the floor to reduce it sitting in water.

 

the roof I would not use insulation tiles but good quality felt or felt tiles with a membrane underneath.

 

heat in summer will certainly be an issue and cold in winter more than you think.

 

my advice would be to rethink if possible, but do appreciate you have to work with what you got.

[RobinofLoxley]

I cant see any possibility of making such a shed usable for modelling. Assuming the door is on the short side, you need probably 3 feet where no railway material is installed just to avoid all the rubbish that will blow in when the door is opened.  AS Andy says, you are not really insulating the shed at all.

 

Any model boards inside will have to be fixed to the floor as the walls arent stable enough. The shed could be a workshop where you build stuff, but medium term nothing built of wood will do well stored in it, it needs to be stored indoors.

[john new]

1 hour ago, Andymsa said:

 

I have to ask what benefit partly insulating the shed would achieve apart from the wasted cost of insulation. But if you did decide to fully insulate don’t forget a vapour barrier.

 

i would try to get any wood off the floor to reduce it sitting in water.

 

the roof I would not use insulation tiles but good quality felt or felt tiles with a membrane underneath.

 

heat in summer will certainly be an issue and cold in winter more than you think.

 

my advice would be to rethink if possible, but do appreciate you have to work with what you got.

Fully concur, the heat / cold thing and lack of ventilation is a major problem with our existing flat roof garage. 

[jonnyuk]

my current layout is an old, damp, dusty garage (single skin with a metal roof) and has fared well (i use marine ply for the base boards). The shed by comparison is a clean environment. 

the base of the shed is off the ground, the air gap between the ground and base of the shed should stop damp rising up.

I do plan on adding a vapour barrier if i do something with the ceiling.

 

So the consensus is don't bother with any insulation, just add vents to aid airflow

Edited May 10, 2022 by jonnyuk

[jonnyuk]

11 hours ago, Andymsa said:

 

I have to ask what benefit partly insulating the shed would achieve apart from the wasted cost of insulation. But if you did decide to fully insulate don’t forget a vapour barrier.

 

i would try to get any wood off the floor to reduce it sitting in water.

 

the roof I would not use insulation tiles but good quality felt or felt tiles with a membrane underneath.

 

heat in summer will certainly be an issue and cold in winter more than you think.

 

my advice would be to rethink if possible, but do appreciate you have to work with what you got.

i maybe was not clear on the roof, the roof is covered with felt, i was going to use insulation tiles on the inside, thinking was to stop cold heat loss through the roof

[Andymsa]

Sorry to say this but your current location is much better than the shed, you will really suffer with the extremes of heat.

[chris p bacon]

I'd insulate the garage rather than half insulate a shed.

 

 

[jcm@gwr]

I've used, and would recommend, a couple of rolls of shed insulation.

It's basically double thickness, silvered bubble-wrap, and you put it up

with a staple gun. also you can tape the overlaps with the special

aluminium tape to get it perfectly airtight.

It has the insulation effect of 2" of expanded polystyrene, and has the

other advantage of leaving an air gap (you staple it to the beams), so

you don't get mould problems.

 

You could also use it in you garage! (and it'll improve your loft, which 

will save you money!)

[AndrewC]

For what it is worth, this is what I did and my shed is now 14 years old. Apart from re-staining the outside a couple of times, and a refresh of the insulation after the original (not foam backed) started to crumble after 10 years, little has changed. 

Shiplap shed from a commercial supplier. Concrete base with their standard floor. I used Halford's interlocking "rubber" flooring which can be replaced easily if there is an accident. (like when I dumped 2 litres of deck stain when the tin's lid popped open) It is also great to kneel on when working under the layout. 

The walls and inside roof were sealed with a vapour barrier and 50mm foil backed foam insulation sheets. The interior is then lined with OSB. 

In winter a greenhouse heater & thermostat keep the inside temp above 7c when not in use. I also have a semi-portable heat pump unit which can bring the shed temp up to 20c in about an hour when the outside temp is -5c. In summer this reverses and it acts as an air conditioner which means I'm comfortable even on the hottest and sunniest day. We installed a freezer about 18 months ago too. 

All of this gives me a working space that I can use year round. (24 by 12) My only wish is the height was a bit better. I'm stuck with the 9' maximum peak the council allows. 

 

Good luck, but the basics are, vapour barrier, some outside ventilation, keep the internal temp above 7c to prevent condensation in winter, and enjoy your space. 

[1466]

My tuppence . 
I have had  a 10x8 shed for 10 years .

Good advice I received :

1. Reinforce the floor with 10 mm plywood. The original floor moved when I walked on it . It’s stable now .

2. Insulate with Celotex honeycomb 2 inch foil backed insulation.  It’s easy to cut and fits perfectly between the 2x2 framework . I was told it’s the equivalent in insulation of 4inches of rock wool.It’s essential to use  a vapour barrier as well . 

My experience has been that I can use the shed all year round. It’s pleasant in winter ( I use an electric back ground heater) but is very hot in summer .

I have a small bathroom type extractor fan which helps a bit but even with the door open it gets to 25 degrees Celsius.

I left small expansion gaps in the track but occasionally have alignment problems… easily solved . Rust hasn’t been a problem but see below .

Although damp hasn’t been  an issue for metals , paper gets a musty smell . I have installed a small dehumidifier which helps .

My shed holds my layout , has a modelling bench and a radio . A ManCave and is ninvaluable.

A big benefit is that I don’t have to put everything away after a session.

I doubt whether partial insulation will help … our loft space is intolerable in summer and winter .

Good luck !

[Quarryscapes]

You'll achieve more by sealing up draughts and reducing air leakage than with only an insulated roof - however you need to be aware that if you vapour barrier it all and get it nice and vapour tight, the vapour you create by being in there and breathing has nowhere to go, so you could end up with condensation problems in your new layout. Have you got windows? 

 

My advice would be insulate every surface evenly with at least 50mm expanded polystyrene or PIR if you can stretch to it. Vapour Barrier inside as long as you can ventilate your space work space (open window, ideally a modern double glazed window with trickle vent). Don't bother trying to ventilate between insulation and shed fabric, it won't achieve much other than potentially scavenging heat through gaps in insulation etc and making an inaccessible space for creepy crawlies to gather. 

 

Golden rules are:

 

1. If a Vapour barrier is present, have it as close to the inside of the room as possible to stop moisture getting into the structure from the inside

2. If there's an airspace created anywhere, ventilate it

 

 

[Harlequin]

If you only partly insulate you may get condensation problems on the uninsulated surfaces.

 

Condensation can be a problem in two ways: Either running down the interior surfaces. getting in the electrics and ruining the layout or building up in the structure and encouraging rot.

 

The vapour barrier is the key to preventing condensation problems. It prevents warm wet air from touching cold surfaces if it's installed on the warm side of the insulation and well-sealed.

 

You also need to think a bit about "cold bridges" - places where there's a path through heat conducting materials from warm to cold. Some cold bridges might be unavoidable in a shed but at least you can be pre-warned that they are the places where condensation is most likely to form.

 

Fixing layout baseboards to the wall will make the shed much stronger!

 

Edited May 10, 2022 by Harlequin

[SouthernRegionSteam]

Without wishing to do the point to death, I'd agree that the garage is likely to be a much better bet; if you're going to insulate somewhere, don't cut corners - as others have said, only insulating part of the building is basically pointless. Here's a comprehensive look at what I did with our single skin brick garage (although it does have a pitched roof, and is slightly wider than a standard single garage):

 

My garage 'studio' build

 

And this is the finished result (minus furniture and bits of trim):

 

 

Cost I think was around the £2.5k mark (done during lockdown). Even with fully insulated everything, it still requires a heater on for a few hours in the winter mornings. Other than that, the temperature is steady, and perfect for a layout. Note that I decided to go for a triple glazed window with a trickle vent at the top. Usually that would be used for kitchens/bathrooms, but I find that leaving it open now and then helps to refresh the air a bit.

 

P.S. I'm no carpenter/builder, so I'm sure there are potentially better ways of going about things.

[Nick C]

My shed is only partially insulated (roof and floor), simply because it's a 'log cabin' type, and it's difficult to attach anything to the walls in those - you can't rigidly join the logs together as they have to be able to move independently as they expand and contract. At least with the logs being 45mm thick, they provide some insulation themselves. I certainly wouldn't recommend it, and wouldn't choose to build such a structure myself (inherited this one from the previous owners)

[jonnyuk]

thank you for all the feedback, very helpful. The garage is coming down, hence the shed.

 

i think i'm on the right track with insulating the roof, insulation tiles and vapour barrier and ventilation.

 

my take away from this though is its pointless without doing the walls. I may have to bite the bullet and do those as well.

[Andymsa]

This is bianca, well that’s the nickname it got after the first wood treatment. It’s is timber framed with roof grade 4x2 framing and has roof trusses. Faced with log lap on facing sides and industrial metal cladding to the sides and rear( fire regs) all fully insulated and has a vapour barrier and has plasterboard inside, the inside is completed to a living standard, the floor is a floating floor and is insulated. It is air conditioned and has a raft foundation. Roof felt tiles with a 35 year lifespan which has further rain protection under the tiles. And all built by myself which saved an absolute fortune employing someone to do it. The marks on the front are due to being prepared for its annual wood treatment. The little building on the end is the garden shed

 

 

 

 

Edited May 10, 2022 by Andymsa

[RobinofLoxley]

3 hours ago, jonnyuk said:

thank you for all the feedback, very helpful. The garage is coming down, hence the shed.

 

i think i'm on the right track with insulating the roof, insulation tiles and vapour barrier and ventilation.

 

my take away from this though is its pointless without doing the walls. I may have to bite the bullet and do those as well.

I think a bit of a porch, with the entrance set at right angles to the shed entrance, so you can get half inside before opening the door, would not go amiss. Remember there might be a lift-out section in front of you, although it should be lifted with you entering. Otherwise the weather may be hitting the layout, depends how sheltered the position is.

[DCB]

The whole rickety garden shed concept sounds like a recipe for frustration.   Mine is on a concrete paving slab base yet it has still managed to tilt over about 10 degrees and had to have a new roof after less than 10 years. and the floor isn't great. That's why I keep the strimmer and push bike in there not the railway.

On 09/05/2022 at 20:35, jonnyuk said:

hi all, after some advice on partially insulating a shed. its 10x8 shiplap clad with pitched roof. the ground work is a weed matt, then plastic base with pea gravel in the honey comb, the shed base is 3  wooden batons, on top of this is single sheet of wood with a shiplap base on top of that. Roof is just wooden sheets with felt over the top.

I have a two window pains that i plan to insulate with perspex on the inside to create an air cavate. 

If you go that route the floor needs strengthening, I would use tongue and groove flooring, and the baseboard structure needs to brace the shed sides. Glass fibre insulation is good but the shiplap will leak and it will get damp, Insulation board inside is how my father in law did his railway shed, which has ply exterior panels, glass fibre insulation, minimal 6" high windows at ceiling height, tongue and groove flooring and subsides because its on individual paving stones not a paved area.

This needs regular jacking up of the low end to keep the level track level.

If you must use a 10x8, design the layout for the shed, like 9ft 4 X 7ft 4, is usable, don't built a train table, but design the layout and build bases for it, that way framing avoids point motors etc not vice versa.  Also use the baseboard framing to brace the shed. L girder with decent size lumber rather than rickety table will get the job done and brace the floor so it doesn't sag as you walk about.  Cross braces, diagonals are good.  A lifting section is just about essential to get in and out and the hinge and landing sides of that needs real serious bracing to the walls and floor.  I replaced the roof on my wooden Garage with tongue and groove cladding around 10 years ago and despite the felt tearing it only needed new felt.  The composite board previously used simply disintegrated when it got wet.   Likewise father in law's shed roof leaked and destroyed several metcalfe card models and warped a fibre board baseboard.    His shed has central heating but still suffers some expansion and contraction issues from winter to summer.   And suffers tarnishing of track from sunlight next to the door window . He can only use the high windows  the low level ones have to have blinds drawn permanently, He should never have had windows, an extractor fan would make far more sense.  Of course you could build the layout in the garden instead,

[RobinofLoxley]

By the end of all these modifications, its an outbuilding not a shed. A typical shed footprint isnt a great starting point.

 

I have had such sheds on my allotments, lots of them on the site and the life depends on doing a lot of maintenance, some of which affects the interior. If not maintained a shed will be in trouble after 5 years and a full rebuild after 10.