Foundation for shed 8x6

cubatahavana

Hi all

I’m getting a 8x6 shed installed in the photo corner. I was thinking of compacting the soil and putting concrete slabs on top for creating a foundation for the shed. Is this a very bad idea? Can I put a membrane below the slabs to prevent weeds/grass growing? Or should I hire someone to do a proper concrete foundation? The shed guys told me that a level garden and some concrete blocks should be ok, but I’m afraid that the soil is a little soft and the shed will sink if supported only on blocks. I thing the slab base would distribute the weight better

cubatahavana

cubatahavana wrote: »

Hi all

I’m getting a 8x6 shed installed in the photo corner. I was thinking of compacting the soil and putting concrete slabs on top for creating a foundation for the shed. Is this a very bad idea? Can I put a membrane below the slabs to prevent weeds/grass growing? Or should I hire someone to do a proper concrete foundation? The shed guys told me that a level garden and some concrete blocks should be ok, but I’m afraid that the soil is a little soft and the shed will sink if supported only on blocks. I thing the slab base would distribute the weight better

See photo

Lumen

The shed will only weigh a couple of hundred kilos, so even with twice it's weight in stuff inside, you're looking at the equivalent of 8 people standing on the soil.

Blocks are fine.

cubatahavana

Lumen wrote: »

The shed will only weigh a couple of hundred kilos, so even with twice it's weight in stuff inside, you're looking at the equivalent of 8 people standing on the soil.

Blocks are fine.

So no need for anything else than the concrete blocks, no paving slab foundation needed?

jt69er

Had an 8 x 12 shed installed last week. Company used blocks and its perfect.
Hoping to sheet inside walls with 12mm ply, should I use nails or screws?

bladespin

Doing the same myself, decided to go with a patio slab base (on compacted hardcore), think it should be good but any further advice would be welcome.

Fine Cheers

jt69er wrote: »

Had an 8 x 12 shed installed last week. Company used blocks and its perfect.
Hoping to sheet inside walls with 12mm ply, should I use nails or screws?

I would suggest screws, easier to take out if required and less hammering of your newly installed shed !

Fine Cheers

Blocks will be fine, ideally 4" solid on flat would be best. No harm for thin base of gravel underneath after you have compacted the soil with a sledge hammer or some dancing.
Loads on youtube, here's one that might suit. Just need to decide quantity needed based on floor construction - shed supplier can advise.

https://www.youtube.com/watch?v=eBlVPVkxsV4

policarp

Fine Cheers wrote: »

Blocks will be fine, ideally 4" solid on flat would be best. No harm for thin base of gravel underneath after you have compacted the soil with a sledge hammer or some dancing.
Loads on youtube, here's one that might suit. Just need to decide quantity needed based on floor construction - shed supplier can advise.

https://www.youtube.com/watch?v=eBlVPVkxsV4

That video is so much OTT.

Lumen

policarp wrote: »

That video is so much OTT.

I watched 7 videos from that series. They're all bad. There are plenty of videos from people who know how to frame properly.

karlitob

Has anyone used these?

https://foundationscrews.ie/

hesker

karlitob wrote: »

Has anyone used these?

https://foundationscrews.ie/

Seriously considered using krinner ground screws when building my shed. Only thing that put me off was prospect of hitting hard ground or rocks which might have necessitated getting a machine in to screw home. Access would have been a problem.

Lumen

karlitob wrote: »

Has anyone used these?

https://foundationscrews.ie/

Not that company but I have used Krinner ground screws.

IMO they're a problem solver. You need to have a reason to avoid conventional foundations.

Fine Cheers

Interesting product and no doubt has its uses.
For me I didn't want any void below my shed based on previous experience with rodents and an older shed.
Part of that was my own fault with the odd rubbish bag stored in the shed when bins full.
Anyway, for the OP yes blocks are ok and yes some of the videos are OTT but hopefully will help you devise a plan. Keep us posted.

karlitob

hesker wrote: »

Seriously considered using krinner ground screws when building my shed. Only thing that put me off was prospect of hitting hard ground or rocks which might have necessitated getting a machine in to screw home. Access would have been a problem.

Good point. I’ve used an petrol auger on quite a number of holes in the back garden. Even a small rock / root can be very difficult to get past.

Any idea what the cost of installation would be these companies? Or can those tools be rented from them?

karlitob

Lumen wrote: »

Not that company but I have used Krinner ground screws.

IMO they're a problem solver. You need to have a reason to avoid conventional foundations.

Noted. Thanks Lumen.

What’s your foundation of choice? I’m putting my plan in at the moment - digging a trench to the back of the garden for utilities etc. I’ll need planning permission as I want to put in a 35/40 sq m garden room. I have the space. 15 sq m workshop and remainder as a garden room.

Putting in a patio currently but need to prepare for the garden room somewhat now.

It’s the crappy part of the garden where the compost heap was so the ground is soft, and smells a bit.

Was thinking of digging out - lob 804 down and finish with blocks all round and in between. For support and to prevent underground critters.

Lumen

Workshop? I would think about thresholds.

If I hadn't had a big slope and massive tree roots to deal with I'd probably have put in an insulated slab.

If I was doing another timber framed garden room on a slope I might do concrete pier foundations. Much easier to get perfect alignment, levels and heights compared to ground screws, at least in my rocky clay soil.

Blocks are fine for a wooden shed though. Keep it simple!

karlitob

Lumen wrote: »

Workshop? I would think about thresholds.

If I hadn't had a big slope and massive tree roots to deal with I'd probably have put in an insulated slab.

If I was doing another timber framed garden room on a slope I might do concrete pier foundations. Much easier to get perfect alignment, levels and heights compared to ground screws, at least in my rocky clay soil.

Blocks are fine for a wooden shed though. Keep it simple!

Thanks for that. I won’t oversell the tools that I’ll have in the workshop. It’ll be part shed, part work area.

What do you mean by thresholds?

Don’t have a slope but was also thinking about concrete pier foundations also?

Thanks again.

cubatahavana

So it looks that the block will be absolutely fine. Should I put a membrane to stop grass?

Are rodents a problem if there’s a gap with the floor?

Lumen

cubatahavana wrote: »

So it looks that the block will be absolutely fine. Should I put a membrane to stop grass?

Are rodents a problem if there’s a gap with the floor?

My last shed sat on blocks for over a decade without rodent problems. Maybe I had them under there, but why would I care? Rats are everywhere. They are only limited by access to food.

I don't see the point in membranes either. Grass needs light to grow, so it won't grow under a shed, it'll only grow near the edges, within reach of a strimmer.

At the end of the day it's just a shed. The only thing that'll ever cause you problems is break ins and damp. If you want to focus effort on something, focus on security, ventilation and maybe guttering. Foundations are a non issue.

ted1

Did a job recently for my mother who was getting a new shed. She had rodents under the old one. So wanted a solid base.

We used a ton of aggregate and slabs we got free of adverts
Came out really well , Broke my heart to put a shed over it.

Whole job only took a few hours