[wil4025]

Hi All,

Ive just bought a 6x8 greenhouse and due to the garden sloping so bad, I went ahead with level concrete base.

First to do it get planks of wood to the size of the base wanted. Make sure at least 12 thick and at least 5" wide. We had used scaffold boards, check ebay. They where £2.50 for 6" and had to join.

The second hard part is digging out a hole to the size of plot wanted and getting level and square. Make sure you have at least 3" on concrete.

I would also suggest at least 1.5 foot around the edges for access, you will want to clean the windows every year.

Once level and square. Make sure everything looks like and make sure base does not go lower than the highest point as you don't want water to run over your base.

At this build stage you can add drainage like ive done, was about £40 with ends and attachment for 100mm pipe. Great as makes sure water goes outside and not left on floor, plus easy to clean floors.

Next do you want electric in your greenhouse, I thought why not. Add lights, heaters etc. More expensive to do, I went for blue water pipe from wickes, 20mm one about £17. 25m 1.5mm Rubber wire from screwfix £25 and drilling a hole to the back of your wall, you can add this to ring main at the back of socket, but I would always ask a qualified electrician to put electrics in, but do the hard work and you can save money. Trick, get some silicon spray and spray cable, this will make your cable so much easier to enter into the 20mm blue pipe.

Once you have done everything above, ready to buy concrete bags, and ballast. For our base we used 1.5 tones plus hardcore, but was very deep at the back and 5 bags of watertight bags of 25kg wickes concrete. Always get more than you need, you can return bags you don't use. Under estimate and you will find wasted time going back half way though. Yes we did. I would also recommend single bags of ballast, if buying 10 a time works out cheaper and if buying a lot like 1.5 tones, works out only £10 more on a jumbo bag, but easier to add to mixer and less work. Mind the car, 10 bags is a lot for most cars to carry. Do it in multiple trips, plus breaking the car will take longer, so take care. Maybe worth checking max weight.

We had a cement mixer we could borrow, but I think for £35-40 you can rent for a weekend.

Two people working is always best.

Set a side at least 4 hour on a good day to do concrete. Check weather report, you need a day for the base to set properly and cover if raining or if frost is forecast then cover also.

Tapping the base once some concrete is added, with wood will get more water out and this makes a nice smooth surface.

The finished result today.

[lassie]

That looks a great job, Bill.

Please can you tell me how to make it totally level? Thanks

[wil4025]

That looks a great job, Bill.

Please can you tell me how to make it totally level? Thanks

You have to make sure all boards around the sides are completely level, then this makes a good level to tamper down the concrete and tap water out of it.

[snowdrops]

That looks a great base,you'll benefit from all the work in years to come.

That looks a great job, Bill.

Please can you tell me how to make it totally level? Thanks

You do need to support the wood very well or the concrete will push it out

[wil4025]

That looks a great base,you'll benefit from all the work in years to come.

That looks a great job, Bill.

Please can you tell me how to make it totally level? Thanks

You do need to support the wood very well or the concrete will push it out

Yes I used a bit of 2x1 stakes screwed to the sides and screwed the corners all with long 3" screws. If you see picture you can see my stakes.

[lassie]

Thanks to both for the info on the stakes and the concrete. What size of boards were used? Will you remove the boards or leave them in place?

I was also wondering if a building warrant or planning permission would be needed when doing a task such as this. We have a big garden so it will not be near the house.

[wil4025]

We used I think 6x1" they are where 6 foot long scaffold boards. I dont think you need permission to lay concrete in your own garden nor do you need permission for a greenhouse or shed. Best to check sizes with your local council though as im sure you cant go massive.

[lassie]

We have dug our founds for a wee wall. 4 inch deep at shallowest end and wide enough for a double brick. Hired a mixer. The builders merchant gave us a sand and gravel mix to use with cement at 4:1 ratio. We will do this work tomorrow morning. Frost is forecast tomorrow night so we will add frostproofer to make it harden quicker and protect it. Maybe we could put some old carpet and plastic sheeting over it too.

[wil4025]

Finished project

[Trillium]

Very nice, Bill. It will look great in MY yard   

[mattyboy]

Hi thanks for the info iv got my greenhouse ready to put up just waiting for the snow to go.
Iv used slabs just got a few to lay then its all systems go lol

[snowdrops]

Jobs a good 'un Bill

[ryetek]

That looks great. I like the drainage idea too. Excellent.

We've just nicely got the base for our greenhouse completed. Like you we also went for a concrete base after starting a thread on the forum and then taking all the replies in to account. This was then followed by much debating with the OH. We didn't do any drainage though so we'll have to see how it goes in practise. I'll try and get a picture of the base posted on the thread I started tonight.

[wil4025]

Thanks for all your comments, was hard work, now im working on getting new patio laid. Got some Indian slate going down