matthyde83 Posted November 30, 2021 Share Posted November 30, 2021 I'm due to start my build in February and I'm facing a few dilemma's that I'm trying to solve now.... Looking for POV and advice please. We are demolishing an existing bungalow to make way for a detached house build. We've previously built a garage on site (last year) so know the ground conditions pretty well. We are on a red clay with lots of flint. We had to go 1.8m in one corner of the garage build to reach chalk, 1-1.5m in other areas. Down one side of the site we have a mature conifer hedge (not lelandi!) but it will probably be c.2-3m from the new house. Few questions... 1. Foundation design or not? BC were obviously happy for a traditional slab for the garage with no prior design work. 2. Builder recommended crushing demolished bungalow and using under a traditional slab rather than ship away plus allows him to use his mini lifter on site to move materials as it can drive over a slab. Thoughts? 3. I've spoken with BC that we used for the garage and he said he's be happy doing on site but said warranty provider may have a say in whether we design in advance given conditions and they would be more stringent than him? Link to comment Share on other sites More sharing options...
Russell griffiths Posted November 30, 2021 Share Posted November 30, 2021 I don’t think you can use any of the crushed old house under your foundations, as they will not comply with any relevant standard. Use all the old house for driveway, and surrounding the house to keep mud down. You need to clarify what you want to build, and how you are building it. What levels of insulation you want and so on, foundation design will lead from this. There are dozens of questions on here repeatedly that say they need a thinner insulation as they cocked up the measurements and now cannot fit in the required insulation. Work out finished floor floor height and work backwards from there. If I had of had a choice it would be an insulated raft for the foundation. Unfortunately im on bad ground so ended up with block n beam which I don’t like much. 1 Link to comment Share on other sites More sharing options...
Jilly Posted November 30, 2021 Share Posted November 30, 2021 3 minutes ago, Russell griffiths said: Unfortunately im on bad ground so ended up with block n beam which I don’t like much. Why's that? I've been told to have this on my piled extension. Link to comment Share on other sites More sharing options...
Dave Jones Posted November 30, 2021 Share Posted November 30, 2021 block and beam every time. Link to comment Share on other sites More sharing options...
Russell griffiths Posted November 30, 2021 Share Posted November 30, 2021 1 minute ago, Jilly said: Why's that? I've been told to have this on my piled extension. We are on piles, ground beneath floor could not be categorised, so safe option is to span over it, then it can do what it wants, shrink,heave whatever. 1 Link to comment Share on other sites More sharing options...
markc Posted November 30, 2021 Share Posted November 30, 2021 If you have a crusher then use the material as temporary hard standing and access etc. if you have to hire a crusher then the cost of that plus all the material sorting will probably cost more than flattening and getting it taken away. Link to comment Share on other sites More sharing options...
Jilly Posted November 30, 2021 Share Posted November 30, 2021 Sorry, I just meant why don't you like block and beam? It looks quite straight forward to do. Link to comment Share on other sites More sharing options...
Faz Posted November 30, 2021 Share Posted November 30, 2021 12 minutes ago, markc said: If you have a crusher then use the material as temporary hard standing and access etc. if you have to hire a crusher then the cost of that plus all the material sorting will probably cost more than flattening and getting it taken away. We had a crusher in last month for a couple of days - cost £300 in hire. Ended up with a pile of 6F2 nearly as high as the house! 1 Link to comment Share on other sites More sharing options...
Declan52 Posted November 30, 2021 Share Posted November 30, 2021 16 minutes ago, Dave Jones said: block and beam every time. If you have good ground conditions and can get away with hardcore and a concrete slab then that's your best option. If you have poor ground that will shrink for eg then block and beam or a poured reinforced concrete slab is your next option. Would be madness to use block and beam if you don't have to. Link to comment Share on other sites More sharing options...
Dave Jones Posted November 30, 2021 Share Posted November 30, 2021 Just now, Declan52 said: If you have good ground conditions and can get away with hardcore and a concrete slab then that's your best option. If you have poor ground that will shrink for eg then block and beam or a poured reinforced concrete slab is your next option. Would be madness to use block and beam if you don't have to. disagree. concrete is hard work and will never be as flat as a screed. They are pretty much cost neutral so B and B every time. Link to comment Share on other sites More sharing options...
Declan52 Posted November 30, 2021 Share Posted November 30, 2021 Just now, Dave Jones said: disagree. concrete is hard work and will never be as flat as a screed. They are pretty much cost neutral so B and B every time. But it's not done as your finished screed. It's a sub floor which gives you a very good base to work from. Insulation on top then your chosen screed type. Having done many a concrete pour and had my back broke moving Beams around and filling with blocks and grouting them up concrete wins every single time. No risk of a block breaking and your ending up on your face when you carrying a cill or concrete lintel. Can load out the house with blocks and bricks much easier. With B&B you have to be very careful that any load is set on an internal wall which is a pain. Link to comment Share on other sites More sharing options...
Dave Jones Posted November 30, 2021 Share Posted November 30, 2021 must be doing them wrong to make hard work of it, loads are designed in so not an issue. Carry on humping conc I know which I and the large housebuilders prefer. Link to comment Share on other sites More sharing options...
matthyde83 Posted November 30, 2021 Author Share Posted November 30, 2021 In response to all of the above... Masonry build 150mm cavity BC understood using the crushed hardcore and seemed ok with it (obviously this is just a call and not an actual decision when it comes to it) Drive has already had tonnes on it from when we built garage so stoned up really well. Can definitely use some under new terrace to rear of house but I'm sure a lot more than that will come out of the bungalow. Understood on finish floor height and work back from that, no problems there. FFL will be same as existing bungalow so need to take out what's there down to whatever level we need. Link to comment Share on other sites More sharing options...
Declan52 Posted November 30, 2021 Share Posted November 30, 2021 Just now, Dave Jones said: must be doing them wrong to make hard work of it, loads are designed in so not an issue. Carry on humping conc I know which I and the large housebuilders prefer. How is it not hard work?? The beams are heavy and need moved into position manually once loaded out with a telehandler. It's not much fun filling them with blocks either. Sounds like an opinion of some one who never got their hands dirty doing one of these jobs. The digger swings the bucket in and tips it out. No humping any concrete. Just needs tampering level. Large housebuilders prefer it cause it takes zero to no skill so employ monkeys to put them in. Saves them money. Just cause they use a particular method doesn't mean it's the best. They are driven by profit not by what's the best method. Link to comment Share on other sites More sharing options...
nod Posted November 30, 2021 Share Posted November 30, 2021 When you contact your Structual Engineer Due to the proximity of the hedge The decision will be made for you Almost certainly Block and Beam Link to comment Share on other sites More sharing options...
saveasteading Posted November 30, 2021 Share Posted November 30, 2021 4 minutes ago, nod said: Due to the proximity of the hedge The decision will be made for you Almost certainly Block and Beam Conifers do not necessarily require deep foundations or suspended floors. What type of trees and what ground do you have? If for example spruce growing at 3m in sand, I don't think there is any extra depth...would have to check though. However , the trees would hang over or near, the house and cast their bits in the gutters, so there could be other reasons to lose them. The Structural Engineer will know what has to be done structurally, but may not consider the aesthetics, health of tree, or gutter clearing onus. We all like to see pictures, and it may help to get the best advice. Link to comment Share on other sites More sharing options...
Russell griffiths Posted November 30, 2021 Share Posted November 30, 2021 1 hour ago, Jilly said: Sorry, I just meant why don't you like block and beam? It looks quite straight forward to do. It’s more bouncy than I would have liked, cold void underneath it. 1 Link to comment Share on other sites More sharing options...
nod Posted November 30, 2021 Share Posted November 30, 2021 35 minutes ago, saveasteading said: Conifers do not necessarily require deep foundations or suspended floors. What type of trees and what ground do you have? If for example spruce growing at 3m in sand, I don't think there is any extra depth...would have to check though. However , the trees would hang over or near, the house and cast their bits in the gutters, so there could be other reasons to lose them. The Structural Engineer will know what has to be done structurally, but may not consider the aesthetics, health of tree, or gutter clearing onus. We all like to see pictures, and it may help to get the best advice. SE normally air on the side of caution While conifers have shallow roots The take a lot of water out of the ground Causing Heave We had deep strip foundations on our first build and expected BB and Clay board Our next has a hawthorn hedge about 8 meters away Excellent ground still BB Majority of the homes I work on are BB Belt and Braces ? Link to comment Share on other sites More sharing options...
Buzz Posted November 30, 2021 Share Posted November 30, 2021 1 hour ago, matthyde83 said: 3. I've spoken with BC that we used for the garage and he said he's be happy doing on site but said warranty provider may have a say in whether we design in advance given conditions and they would be more stringent than him? Sound advice , I would first check with your warranty provider as to the level of detail they require to sign this part off , do they want a full survey and design or a simple soil survey report and recommendations and would then be happy to accept the BC and builders decision based on the reports findings. Link to comment Share on other sites More sharing options...
matthyde83 Posted November 30, 2021 Author Share Posted November 30, 2021 1 minute ago, Buzz said: Sound advice , I would first check with your warranty provider as to the level of detail they require to sign this part off , do they want a full survey and design or a simple soil survey report and recommendations and would then be happy to accept the BC and builders decision based on the reports findings. ok thanks… one of the decisions I’m trying to make is SE or not. I also don’t have a warranty in place yet (starting Feb). Trying to get ahead of myself as much as poss! Link to comment Share on other sites More sharing options...
matthyde83 Posted November 30, 2021 Author Share Posted November 30, 2021 50 minutes ago, saveasteading said: Conifers do not necessarily require deep foundations or suspended floors. What type of trees and what ground do you have? If for example spruce growing at 3m in sand, I don't think there is any extra depth...would have to check though. However , the trees would hang over or near, the house and cast their bits in the gutters, so there could be other reasons to lose them. The Structural Engineer will know what has to be done structurally, but may not consider the aesthetics, health of tree, or gutter clearing onus. We all like to see pictures, and it may help to get the best advice. How about this… Link to comment Share on other sites More sharing options...
Buzz Posted November 30, 2021 Share Posted November 30, 2021 15 minutes ago, matthyde83 said: ok thanks… one of the decisions I’m trying to make is SE or not. I also don’t have a warranty in place yet (starting Feb). Trying to get ahead of myself as much as poss! Whatever route you choose to go down i would check on availability ASAP i was quoted 6 to 8 weeks by several companies for soil samples back in the summer, most SE will do their own and then do the design your might have a bit of a shock as to when they can fit you in . Link to comment Share on other sites More sharing options...
nod Posted November 30, 2021 Share Posted November 30, 2021 26 minutes ago, matthyde83 said: ok thanks… one of the decisions I’m trying to make is SE or not. I also don’t have a warranty in place yet (starting Feb). Trying to get ahead of myself as much as poss! You won’t have much choice Planners will insist on a foundation design Probably the best few hundred quid you will spend Link to comment Share on other sites More sharing options...
matthyde83 Posted November 30, 2021 Author Share Posted November 30, 2021 2 minutes ago, nod said: You won’t have much choice Planners will insist on a foundation design Probably the best few hundred quid you will spend planners?? already has full planning and BC confirmed earlier they will happily deal with it on site. q is will structural warranty want more… Link to comment Share on other sites More sharing options...
SteamyTea Posted November 30, 2021 Share Posted November 30, 2021 Decide on the thermal losses and then work from that. Link to comment Share on other sites More sharing options...
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