wooden shed onto concrete...dpm barrier between surfaces?

[steveo3002]

need to do some repair work on our wooden shed , the wooden bearers/crossmembers sit on concrete , would i be best to put some dpm barrier between the two surfaces

 

[Dee J]

Yes. Anything to stop the timber wicking up water.

 

[brightspark]

wont do any harm treat them while your at it ,mine are coated with genuine creosote well over 40 years ago now

 

[lchris21]

Yes. Anything to stop the timber wicking up water.

wouldn't the timbers still wick up water off the DPM? ...............ive got mine sat on spaced out pieces of slate the width of the timber base.

 

[knighty]

yes it'll help.... but a line of bricks or something to lift them up a bit would be even better

 

[steveo3002]

i was hoping to make some sort of stand off /row of bricks to keep it above where water would collect , but still you have wood meeting concrete sooner or later

 

[keithski122]

I've just bought a new shed and was going to ask a very similar question.For our last shed the builders said to rest it on damp course.This time I wondered about wrapping it up the sides of the bearers. Instead I bought some plastic garden mesh stuff thats 40mm thick to rest the whole shed on.Cost was just over £60 for a 8x6 shed.Check out ecodeck, buy from ebay as its cheaper than from their website.

 

[Agrismith]

It is an optional extra to have dpm fitted to all the sheds and stables we install from all different brands. I don't think it matters to much if there is airflow. But without airflow anything will help

 

[roofman]

I sat my timbers on 9mm thick UVPC flat board cut down the width of the timber... still bone dry after 10 years

 

[gaz1]

there also composite instead of wood

Plastic Lumber Joist 50x100mm | EnviroBuild

Heavy Duty support for your deck using Manticore Lumber recycled plastic joists - 50x100mm available in 3.4m lengths

www.envirobuild.com

 

[voipio]

Might be worth running a bead of Sikaflex EBT+ along the outside base of the wall of the shed and the DPM, to stop water getting in between DPM and shed base.

 

[steveo3002]

Might be worth running a bead of Sikaflex EBT+ along the outside base of the wall of the shed and the DPM, to stop water getting in between DPM and shed base.

yeah did cross my mind.....then i cant use creosote /engine oil on the timber

i guess if it lasts 20 years i will be dead by then...maybe im overthinking it lol

 

[knighty]

there also composite instead of wood

Plastic Lumber Joist 50x100mm | EnviroBuild

Heavy Duty support for your deck using Manticore Lumber recycled plastic joists - 50x100mm available in 3.4m lengths

www.envirobuild.com

are those solid plastic? I thought about using plastic decking to lift a walk in freezer off the floor - but a mate told me it's not solid plastic it's more plie plastic+mdf?

 

[addjunkie]

I sat my timbers on 9mm thick UVPC flat board cut down the width of the timber... still bone dry after 10 years

My green house sits on 1/2 neoprene. I used Stock board cut up for the chicken coup, seems to have worked well. My shed sits on 1 layer of engineering brick, with dpm on top of the brick, woods nice and dry

 

[steveo3002]

^ whats that please 1/2 inch? neoprene ? is that the stuff light gaskets are made from etc?

 

[sako243]

My first little shed in Surrey I got a thick "builders plastic sheet", blue dpm for want of a better description. Stapled it up around the bottom frame so it went up 3-4 inches and then put the cladding over the top of it. Of course any water that got in would stay but never had an issue with that. If you were so inclined you could possibly cut a channel and have a drain hole in the centre.

 

[gaz1]

are those solid plastic? I thought about using plastic decking to lift a walk in freezer off the floor - but a mate told me it's not solid plastic it's more plie plastic+mdf?

yes they need chopping out with a metal blade in a chopsaw as they can have metal shards in them
there is also a little bit of weight to them compared to the wood alternative

you can get beams as well in the same stuff

Large Plastic Lumber Beam 75x125mm | EnviroBuild

Heavy Duty support with Manticore Lumber recycled plastic beams - 75x125mm available in 3.4m lengths

www.envirobuild.com

Please note, due to the recycling process, small metal fragments can end up within the material, use tungsten carbide tipped saw blades when cutting these lumber profiles.

• Made from 100% recycled plastic and fully recyclable

 

[bricol]

Sat two of my sheds on sleepers, that were themselves above local ground level. Both sheds seem fine.

Sat another on rows of bricks under the bearers, a lot closer to the ground. It seems knackered.

 

[brightspark]

mines sat on 3x3 planks 8 foot long on gravel there as good as new

 

[addjunkie]

^ whats that please 1/2 inch? neoprene ? is that the stuff light gaskets are made from etc?

Yes basically thick gasket material. Just lifts thewood from the concrete and helps seal the tamped surface. Where as using recycled bale wrap, ie stock board, or the posts, is quite hard so can allow water underneath espescially on a rougher concrete finish

This is stock board, which is recycled bale wrap, makes a good water proof layer with many uses. They do fence posts etc too. https://www.solwayrecycling.co.uk/shop