Andy H

Thanks Russell I had considered a low retaining wall and then building within it but as I am already at the neighbouring boundaries it would mean I would have to reduce the size of the building which I would prefer not to do. It would however mean the building would be far less suceptable to water / damp penetratioI. I costed it out at around £12k and this combined with a smaller building makes me reluctant to go down this route. I spoke with one of the technical people at NSBRC and their suggestion was to backfill with waterproof concrete which would also act as a retaining wall and prevent the need and cost of formwork whilst maintaining the maximum building size. I would be interested to hear other peoples views on this. Andy

Thanks for the video. Could you let us know which system you used for the insulated slab and whether you would recomend it? Kind regards Andy

Would you say it was reasonably easy to learn? It sounds like a good skill to learn. Andy

Thats an interesting idea. I had been pondering the idea of trying to learn a simple CAD package but the fiverr.com route would be alot more expedient! Thanks Andy

Its reassuring to hear your surveyor comments. Its quite surprising that a structural engineer would not know, given your location it couldnt be a water table problem! Thanks Andy

I didnt go for planning for a couple of reasons - 1 By keeping at 2.5m above ground level the building will not be too visually imposing. 2. I was able to agree with a neighbour to aquire a very small section of their garden which meant I could build a larger building, but the condition was not to go above 2.5m. I have appointed a building inspector based on recomendation and they have been helpful to date.

Yes- I will be going overboard with the waterproofing plan - expect some future posts into the forum!

Yes the FFL will be around 0.75m below ground level in order to get more height within the building whilst fitting within permittesd development rights.

Good evening Dave, I started last summer and thought I would be able to get the foundations and ICF walls up but a combination of me being too slow, too ambitious and delayed by the structural engineer resulted in me making the decision to shut up for the winter. I am now doing the prep work for a spring start and hopefully a water tight building before the end of summer. I live in one of the highest locations in London and my understanding is that the water table in London is below the level of the London Underground. If the watertable was 1m below my garden I assume water would be seeping out through the ground in the rest of London. I presume the reason the water is not draining away is because it is sat on clay which is slow to drain?

What is FFL??

My plan is to do the same as you - run the sump pump into the drains

Russell I am building a 6m*12m building under permited development rights at the bottom of my garden, close to neighbouring boundaries so I am limited to a height above ground of 2.5m. I have dug down in order to get more height into the building whilst keeping within permitted development. I am planning on an ICF build sat on a isoquick insulated slab. I have attached a sketch fyi Any comments would be welcome

The building and foundations are well above the water table. It just strikes me that my garden and surrrounding gardens are going to be dumping alot of water into the permeable back fill and put alot of demand on a sump pump. The foundation will be sat on clay so it wont drain away into the soil below the building. Approx the first 1 foot of the soil is permeable top soil, below that is clay

The buildings walls will be retaining using steel reinforced concrete within ICF. I haven't decided whether to go for eps or woodcrete yet. I will be relying on a structural engineer to provide the exact specification of the wall.

I was intending having a sump and pumping out but think it makes more sense to prevent or reduce the water draining from the garden to the foundations, therby reducing the likelihood of water penetrating the building at some point - I am planning on appropriate waterproofing of course.

I am planning a single storey building which will sit on foundations around 1m below ground. I completed the excavation last summer and boarded up to start again this spring. After a days rain the hole can contain 5-6 inches of water suggesting that alot of water is flowing in from my garden and neighbouring gardens. Most of the research I have done on line suggests the use of a water permeable material for my back fill along with a french drain at the base of the foundation. Wouldnt this mean the garden water would then drain into the backfill around the building wall and foundations? That would be alot of water passing the wall and alot of pumping out. It would seem more common sense to prevent the water getting around the below ground walls and foundations in the first place. I have come across foam concrete which I thought may be able to serve the purpose of backfill and keeping the water away from the building. Any clarification would be appreciated Andy

I am constructing a single storey ICF building with 3 sides being close to neighbouring boundaries and not visible. What would be the options for rendering these 3 elevations economically? Thanks - Andy

Thanks for giving this information. I am considering woodcrete and one of the attractions was the lack of proping and related cost - Iooks like I will need to omit this as one of the pros for woodcrete.

Has anybody had more recent experience with buying Logix blocks ( from Build Better Homes) as I have been doing comparison pricing and found them cheaper. They are also the supplier of Isoquick insulated foundations which I am considering but am a little wary given Willbish's experience.

That sounds like you were productive. Which ICF supplier did you use? Kind regards Andy

Could you expand on why you pick out Amvic from all the other suppliers? I had chosen Nudura and paid up for their training day which is currently on hold. This is given me time to be able to reconsider ICF supplier so would welcome any comments you have re Amvic. I have placed a request for contact with them but so far they have been silent. Kind regards Andy

Thanks for pointing this out. I have decided I am building with ICF but am undecided on whether to use woodcrete or eps. For the purpose of getting provisional budget comparisons do you know whether the amount of rebar to be used in an EPS ICF build would amount to a significant cost compared to woodcrete for a single storey building. I know ultimately I will have to use a structural engineer to specify the amount of rebar to be used but I would rather not have them run multiple calculations for different suppliers, incurring more cost. Thanks Andy

Thank you for this. I am at the stage of having chosen ICF as my build method but not the supplier. I am surprised at the difference in concrete required between the suppliers using eps-are all concrete thicnesses the same?

Could you expand on this please. I am planning to do an ICF build with the the first course starting at 0.7-0.8m underground but am not clear what you are meaning. Thanks Andy Just found the explanation in a later comment - you mean that as the concrete is within the ICF you cant inspect it

https://collier-stevens.co.uk/faqs/general-party-wall-questions/#what-do-i-need-to-do-now this link may help you decide-scroll down and there is a flow diagram