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Base prep for new shed

I am currently looking at buying a new shed (floor included). I intend to have a concrete base laid to put it on but have noticed that some people put the shed directly on to the concrete base and others have it raised up a few cm's off the floor on a wooden plinth. Which way is better? and why do they raise it up? I am guessing it is to do with the floor getting damp. Any suggestions for a robust tanalised shed (approx 15' x8') welcome. Thanks


  • purplerallimpurplerallim LincolnshirePosts: 2,670
    Yes a raised shed is better the wood gives you air to keep the damp away and gives you a good 20 to 30 years use of your shed instead of maybe 10 before it rots. Also remember to put guttering on or your walls will get damp, good place to put a water butt.😁
  • Bromley, KentPosts: 127
    A popular workaround is to lay the shed on concrete fence posts. You may have to cut them to length but you can get them level at your leisure and plonk the shed on top, giving you 100mm clearance underneath for air circulation. I'd scrunch up some chicken wire underneath if you're worried about foxes etc 
  • MeomyeMeomye Posts: 557
    Thanks for replies, Purplerallim, do I need guttering if it is an apex type shed?, if I go with the fence posts method, would the guys delivering and erecting it be ok to mount it on it for me? Thanks
  • purplerallimpurplerallim LincolnshirePosts: 2,670
    The guys erecting the shed will be very pleased if the base is ready for them. And yes any slope on the roof needs guttering to protect the shed.I inherited a shed in my new garden without guttering and one wall is rotting and damp the floor is giving way too, so the next job is removal and maybe raised veg beds in it's place as there is enough storage elsewhere.
  • KT53KT53 Posts: 4,071
    You need to check with the suppliers to ensure that any base you prepare is OK for the floor they will be using.  If using concrete posts or similar they need to be laid at right angle to the timber floor joists and at a spacing which won't allow the floor to sag betwen them.  Also be aware that many concrete fence posts taper towards the top so wouldn't get a flat base.
  • Bromley, KentPosts: 127
    Yes, obviously check with the suppliers, and set your posts in the right place to suit the shed dimensions. A bit of work but so much less than laying a concrete base, and a lot cheaper. 
  • MeomyeMeomye Posts: 557 I have just read on a shed supplier's website that if you have a concrete base you do not need concrete shed bearers. Were you suggesting putting shed straight onto bearers with no base?
  • FireFire LondonPosts: 6,237
    edited June 2018
    I have seen people just put blocks of unmortared paving on sand underneath, does that not work too, for a small shed? I would say guttering depends on the size of the shed. My little tool shed is bone dry without anything, it just has a sloping flat roof. It's very sheltered, in the crook between fences and under a tree. This is quite fine as is for a simple shed. The shed is also not raised and has been good and strong for 20 years.
  • hogweedhogweed Central ScotlandPosts: 3,975
    The company erecting the shed should sit it on blocks or whatever - ask them as it should be part of the shed price. You are only responsible for the groundworks. 
    'Optimism is the faith that leads to achievement' - Helen Keller
  • Bromley, KentPosts: 127
    I see you can buy concrete shed bearers but fence posts will do.
    They can go straight on to the soil and be packed out level with sharp sand or mortar. I usually end up pushing it under the edges with my fingers.
    Small sheds can be stood on house bricks as long as they're firm and level but, whatever system you use, leave a space all round so you have access to replace the roof felt when the time comes. 
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