Thread: Insulating the shed

Just a note on insulation and condensation. There is often some confusion about where the water in condensation comes from or how it gets there.
Any moisture in the slab (or from leaks into the shed), any evaporation form water containing materials used in the shed, and of course the perspiration and respiration of the workers in it is evaporated into the air in the shed. This air is warmed up by people, machines, re-radiating walls and roof when the sun shines and ay heating provided. The warmer the air the more water it can 'carry' as vapour.
At night, in winter or during cold rain, this moisture laden air is warmer than the walls and the roof and when it touches these, will cool down and 'let go' of the vapour which condenses back to water.
The principle with vapour barriers and insulation is to ensure that the vapour barrier (plastic, metal or bitumenous foil - or even vapour-proof paint) in on the INSIDE of the insulation! If its on the outside or there isn't any, the point where the air gives off its water (the dewpoint) may well be IN THE MIDDLE of the insulation, making it wet and ineffective! I've enen seen fibre insulation get so wet and heavy over time it brought the whole ceiling down!
This vapour barrier obviously needs to be sealed, for example taped at the joints.
You often see aluminium foil fixed to the roof battens and following the slope of the roof.
This is called 'sarking' and is meant to allow condensation and any wind driven leaks to keep away from the insulation. If there is enough slope and enough air space above the ceiling, this woks ok, as the dew point is then somewhere above the insulation in the ceiling space and the condensation runs down the inside of the sarking and can be channelled to the outside of the insulation - with good design.
In a shed, typically with little slope of the roof or with little air space above the ceiling, it is better to have a vapour barrier on the inside of the insulation, to prevent any moisture migrating into or through the insulation at all, and ventilating the inside moist air some other way. Sarking is still a good idea - in addition to the vapour barrier - particularly in humid climate and to prevent wind-driven leaks through the roof.
By the way, some expanded foam insulation sheets and the like are vapur proof without a separate vapour barrier.
Hope that explanation helps.
Cheers,
Joe

The bitumen chaulk has worked wonders. Moisture and small pools of water are pooling on the outside of the shed on the slab and not getting inside. Today I finished lining the shed. It took me 9 hours even though it is a small shed. I put Pink Bats Sonic on the neighbours side and lined it with non structural ply - complete silence on the neighbour's side. The rest of the shed is done with Bradford Thermal bats and lined with the same ply. It reduced the temperature as I was lining it and was cool this afternoon when I finished - after I had lost about 2 kilos in sweat.

I have left a small area of metal exposed where I will mount an old mobile aircon to keep it cool when I am working in there. Tomorrow I have conscripted my sons-in-law in the afternoon to give me a hand moving my work benches from the other house. So, by my next day off on Wednesday I am hoping to have everything set up to start turning another pen.

Thanks everyone for your advice

Greg

Good to hear it's worked out for you.

The 'furniture' went into the shed today and tomorrow the tools will be fittted. I had my sons-in-law over for the afternoon to help moving the heavy stuff. Every square inch is catered for. I will post some pics tomorrow.

Every square inch catered for, now where is the room for expansion?

Originally Posted by plantagenon

The 'furniture' went into the shed today and tomorrow the tools will be fittted. I had my sons-in-law over for the afternoon to help moving the heavy stuff. Every square inch is catered for. I will post some pics tomorrow.

My son came over and did the same.

Okey Dokey

For those who have been watching I have attached the photos to show you just how much can be squeezed into a small shed. Also, I found the best product to seal the shed to the concrete is Betta Bitumen Rubber available from Bunnings. It really waterproofs it but finishing the sealer with pain is a necessity - when the slab dries out. ALSO, if you are getting a shed put up make sure the slab is designed for it to avoid leaks - mine was not. Almost forgot - the unfinished bit at the back left of the shed is to allow an airconditioner to be fitted. Finish is a bit rough but practical as it is insulated, fairly cool and very quiet.

OK, I give up. A huge storm this afternoon and water pouring in under the base of the shed. Any ideas. I have tried everything. The photos above show the shed just sitting on the concrete slab which was not made to allow the edges of the shed to sit lower than the internal slab height. Should I use a flashing down the outside of the shed over the concrete and to the ground, if so, shich one? Or should I get a bitumen sealing company in to seal the outside?

Have been following this and can feel the distress. Do you have gutters for this shed? There is another thread about concrete being level with the roller door and water coming in.
Not able to copy link from the device that I am using to reply, but one suggestion was to grind the concrete with angle grinder.

That's going to be one incredible job to undertake for your shed.

Sounds like a frustrating situation. It's a shame that the edge of the sheet doesn't run slightly past the edge of the slab.

Yours obviously has an oversized slab and the shed on top which seems to be causing a few issues. Not the best looking solution but I would get a flashing made up that runs vertically on the inside face of your external cladding, bent under the external sheet , runs on a slight fall horizontally along the slab apron and then finally folds vertically over the edge of the slab.

A lot of work. Particularly now the shed is lined but it should solve your problem. If the water is getting under the door then that is another issue.

Keep us updated.

Stinky

I should have added you can get the flashing folded to suit your situation based off your site measurements.

Another look at the photos indicate that it will not be as visible as I had initially thought. You want the flashing on the inside face of your external sheet so any water running down the face of your sheet will be diverted by the flashing.

Looking at your setup I would honestly consider getting a small jackhammer and chipping he 3" off the sides of the slab might be worth a go.

I have thought about the jackhammer solution but I think it will be nightmare, particularly with the reinforcing in the concrete. I was also thinking about drilling a couple of holes through the edge of the slab at a 45 degree angle to drain any water that might get in. However, I have been onto the glue companies and am waiting for them to get back to me with a possible solution. It is a real pain as each time the floor dries out, it bloody rains again.

I took the centre out of a few baby's nappies the other day and put them on the floor. The result was the water was absorbed almost immediately Some super absorbent polymer might be a temporary solution. I have also thought about putting Bear aluminium flashing (with the black bitumen sealer on the other side) around the outside of the shed and over the edge of the slab to allow water to run off the slab.

Something will come up eventually, I hope

The silicone you used to seal the shed might be part of the problem; it doesn't seem to like sticking to concrete - we used a polyurethane sealant instead as it's used for conrete.

Your idea of putting some sheeting lower down on a 45 degree angle to cover the concrete and make the water run off it onto the ground sounds like something I would try out