New garden shed with composite cladding

Fine Cheers

Going to build a simple lean-to shed in corner of garden using the existing blockwork boundary walls for 2 sides. Other 2 sides to be composite t&g cladding laid horizontally on treated timber stud with corrugated metal clad roof. Base to be concrete slab.
I see some sheds (mainly timber) put in a membrane to inside of walls I assume as a further layer of protection to elements. Don't think I need this for the composite cladding but comments welcome. Shed will be for lawnmower, bikes etc so no plans to insulate for now. Do I need to consider condensation, I don't think I do but again comments welcome ?
Also thinking of a sheet of OSB under the roof cladding just to help with fixing of perimeter trims but maybe this is overkill ??

listermint

Always use a membrane. It doesn't matter if the cladding was made of titanium. You put membrane underneath. Breathable one.

Calahonda52

How will you mange the damp from the two side walls?
you need good ventilation.
is the composite not insulated?
If they are sealed units then I see no need for the membrane as the cladding is 100% impervious, same idea as when membrane is used on alu clad ups/eps: wasted

G-Man

If you are saving a lot of material, using the walls might be worthwhile, but consider how you deal it against driving rain... Also a vapor barrier provides a small amount of insulation to stop internal damp air condensing on cool walls.

listermint

Calahonda52 wrote: »

How will you mange the damp from the two side walls?
you need good ventilation.
is the composite not insulated?
If they are sealed units then I see no need for the membrane as the cladding is 100% impervious, same idea as when membrane is used on alu clad ups/eps: wasted

Roof Slates are impervious, Why do you put membrane underneath them ?

Calahonda52

listermint wrote: »

Roof Slates are impervious, Why do you put membrane underneath them ?

You know and I know you know that is a mischievous question:D.
https://www.nsai.ie/about/news/publication-of-sr-542014-code-of-practice

Lumen

G-Man wrote: »

If you are saving a lot of material, using the walls might be worthwhile, but consider how you deal it against driving rain... Also a vapor barrier provides a small amount of insulation to stop internal damp air condensing on cool walls.

The thing is though, isn't it relatively good to have condensation on walls? I mean not in a house, but in an unheated shed for tools and bikes.

If the water is condensing on the walls because they are colder then it's not condensing on the stuff in the shed, which is warmer than the walls.

I find this whole area really confusing. Houses are kept dry by being heated and ventilated, but when there's no heating...?

Calahonda52

My experience of sheds is that the tools never warm up and will always be below wall temp.
IMO If you have condo on the inside wall of a steel shed, then its worse as the sun will drive it off and where will it go.....?

The only viable solutions I have seen that for the valuable small hand tools you build a press with a low watt bulb on a temp or RH stat

This where i keep my extensive collection of lie nielsen planes.... just kidding!

Fine Cheers

Thanks all. The blockwork walls are 9" hollow both sides. Lean-to roof will go directly underneath existing precast wall capping along one side which has a circa 50mm overhang. I will put a strip of flashband or similar all along just to be sure. Likewise with the junction of other wall. Mastic first then flashband over. Not overly concerned re damp getting through the hollow block - it is rendered on the other side and it is just a shed for bikes, lawnmower etc. Roof to be single skin non-insulated currugated metal sheet.

Fine Cheers

Here's a few photos of cladding on timber frame which I did for front gates / side panel. See also image of proposed roof sheet. Fairly good overlap at cladding joint so don't see need for breather membrane. Are some of ye suggesting to fit breather to block walls also using battens ?? Planning on ventilation via voids under corrugations - leave out some or all foam fillers. 300mm overhang at wall plate so should be ok weather wise.

Calahonda52

Okay, I completely mis read what you meant by composite cladding so my apologies if I wronged anyone here
DK, how is it fixed?

Fine Cheers

Secret fix into tongue similar to T&G boarding. Use clips on first row.
Apologies, I see now that 'composite cladding' in the title may have been misleading !

vintcerf

where is the cladding from? looks really nice

Fine Cheers

https://timberireland.ie/pura-cladding-20x120x4000/

They have a display area with all the colours and types. Not cheap but maintenance free !
Arrange your own delivery as their courier seems to charge per pallet space which adds up.