mrfish

My plans are being drawn up at the moment. I will post them when they are done 5.1m by 3.3m. I will be making it out of SIP panels from https://www.secondsandco.co.uk/product-page/s-i-p-panel-172-mm-thick-1-220-x-5-400-5-500-long I have bought 3 sip knives as a second hand job lot from eBay.com, they are on their way now. My guesstimate for the completed shell, not including electrics or combi central heating/HW is £10,000

If you hit ground it will be sand but for most of it, it will be Victorian brick as a WWII bomb took out the Vic terrace house that was there and they just collapsed the foundations into the basement so if you scratch the topsoil off it is just brick, but, it will extend beyond the old base of the Vic house onto sand. There is about 30cm of clay before the sand.

I don't suppose you know about centres for the ground screws? If I have to put beams on the screws I might lose too much head height. If was to go the concrete base route how deep would the base need to be?

Many thanks for the replies so far. Would the SIP shed rest directly on the anchors or would I put joists on top and it rest on the joists. Obviously height is a major consideration as I will be losing about 40cm with the sips and the plasterboard inside.

Many thanks for the superb advice I have received on this site so far. It has been amazing. Has anyone had any experience using ground screws for the foundations of a garden office? Any advice would be greatly appreciated.

If you or anyone else can find me a suppler who will sell them to me I will buy them. But now you mentioned the 142s can be cut to size that solves my problem. Many thanks.

I hadn't thought of making my own. That is a very interesting idea and could be done very simply. Thank you.

Sometimes the obvious is wrong. This is one of those occasions.

Many thanks for the help I have got on here so far. Does anyone know where I can buy some splines for Kingspan Sips. I emailed Kingspan but I didn't get a reply.

If you look on youtube the Septics use a chainsaw. It's a tough call as to whether the kit or the panels would be a better option. I would be going for the 142mm ones. All it is, is a box, it can't be that hard to make out of panels

Does anyone know anywhere in this country where you can buy a hot knife for gouging out the SIP insulation? If you could lay your hands on one of those you could just buy panels and make the box yourself. I have looked and can't find one for sale in the UK. http://www.ebay.com/itm/L-H-Electric-Foam-Scoop-Hot-Knife-SIP-Panel-Scoop-7-25-Wide-750-Watt-NEW-/262944502357?hash=item3d38b6b255:g:GEUAAOSwmCVY9-Er

If you use this company please keep us up to speed on how it goes.

Please PM me both the installers and the Kent company and the company that was shite as I want to make sure I don't use them.

I would really appreciate feedback if you use or go and see him.

How did the build go? Were there any problems, missing parts etc? The one that Dave posted on eBay looked really good but has zero feedback as a seller and only a mobile number so I am not keen to use him.