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About DeanAlan

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  1. @Roger440in a prefect world, I am looking to improve the airtightness of this property as a I renovate. The extension (150% additional size) will have reasonable (beyond building regs) attention in this area and would like to bring the older part of the property up to similar level (the original 86sqm property will be basically taken back to its external walls and roof structure with replacement ground floor structure etc). If my current DPC is badly compromised (still a question really) and I am having EWI installed (which will reduce the external breathability of the solid walls to a point you made earlier) then feels like my options are narrowing in that I'm going to need to let the walls breath internally more (lime plaster?). It could be the DPC is fine (I did notice, for example, that the DPC had been mortared over externally in a few places and plastered over internally and these are therefore both moisture bridges - i'll get the external ones fixed before EWI goes on) and that the dampness originated from condensation. cheers, -Dean
  2. So I've found plenty of tank options for this project and my preference is for an outer tank with 600m+ greater radius and to put one inside the other and use it to form the concrete and give double the waterproofing. One concern I have is displacement pressure - not sure if this is the same as heave/hydrostatic pressure. If I used the single tank approach and poor concrete then I think there is a great chance that the outer concrete will gradually leak water and cause the inner tank to be pushed up - float. Whilst it will have bottles of wine in, it is not going to weigh more than the body of water (1m of it would be below water table) it is displacing. With the double tank approach then the weight of the concrete is within the boat (so to say). Concrete is about 2.5 (little less I think) denser than water so (in pure tank terms) if half the tank is below the water table then the bottom half(ish) of that (quarter of the tanks depth) would need to be filled with concrete. Does that sounds right? So a 2m deep tank sitting flush with ground level where water table (it is very high at the moment) is 1m bellow ground would require 1/2.5 of the that 1m height displacement to be concrete to counter the displacement upward pressure. The maths is more complicate for the double tank approach (I can work it out) but whilst the outer tank is bigger (more displacement, more upthrust) the full height of the concrete wall (300m ish thick) adds to the weight of the boat trying to avoid floating. If the cellar wall was part of the house structure then the weight of the house would bare down on it as well which would be massive but at the moment I had it sitting below, and unbound, block and beam floor. I feel my cellar is floating but the idea is sinking a little. If my outer tank is a 6000ltr tank and the inner one is 5000ltr then I have (in ltr) 1000ltr of water volume to replace with concrete in the walls so at 2.5 density ratio is 2500ltr. The water table is half way up the 6000ltr tank so 3000ltr of water displaced by 2500ltr of concrete - that boat is floating, not resting on the sea bed. I need another 500ltr of weight and at .75ltr per bottle of wine I would need to keep 666 bottles of wine permanently stored there. Maths has never been so much fun 🙂 My SE is going to love me. cheers, - Dean PS just find this SE design workup for spiral wine cellar. Beyond me but it talk about the stuff above in a LOT more detail
  3. @Gus Potter up for spending £15 to say £1k. @Roger440 yes, EWI outside (with its own member) and then DPM lapping up the wall 600mm of so is just going to create a wall of brick tanked either side so the capillary action will suck up the water and it will not have opportunity to evaporate away given the membranes. When you say treat the building as if it doesn't have a DPC, what would that be? @Adsibob hope we solve our floor lowering and damp problems. Our water table (as off two days ago and the heavy rain) about 1m below ground level but our current floor is 600m above that. I have another thread on here where I'm looking at digging a cellar below the water table which is generating some cool ideas. cheers, -Dean
  4. Looks like we (and I do mean "we" ) have a plan here. I'm going to run the (second hand) tank idea, filled with water and cast around idea past my SE and watch his expression. I was almost wondering whether two tanks would be better. If I could find inner one of 2m and outer one of 2.6+. Cut end of outer one, drop it in, drop in some block to make sure there is a gap, pour bottom slab to the level of the blocks, drop in the inner one, start filling inner one with water and then start pumping concrete into the gap between them (maybe with steel mesh I would have had to preformed to 2.25m diameter. When concrete has started to go off, cut top of inner one and (actually, why would I fill with water when it is a wine cellar, I could make it a wine tank 🙂 ) I'll let you all know my SE feedback and then share progress. Likely not until March. cheers, -Dean Much thanks @PeterW and @MortarThePoint
  5. If I dropped a in tank like that one @PeterW (nice find - as an example) I wonder whether I would need a concrete base (externally) suspect not. Then pour concrete around the outside (a waterproof concrete mixture I guess, or at least one that will set underwater - you can get that can't you - probably called marine concrete or something, I can't google and type at the same time.). Concrete floor internally but more for weight and solidity under foot. The external concrete would be for strength - retaining wall effectively. This is sounds cheaper by the minute - can't be right! Might even have some money left buy a bottle of wine to put in the middle. [aside: these wine cellars can hold circa 1000 bottles, I can't afford that much good wine] - Dean
  6. Some great ideas here @PeterW and @MortarThePoint Water in the tank before pouring concrete - if that was the approach I took rather than formed (square) from blocks. Might have to get the Firebrigade out to fill it and empty it. Was looking at products and likely over 4000ltr ( Ideas - keep'n'coming cheers, - Dean
  7. @MortarThePoint yes that reminds me, that is why I had thought that it was probably better to build the structure square. My initial idea was those inspection rings but less keen now. On the topic of the block and bean - thinking that actually maybe the right thing to do is (for the half that has solid ceiling) bridge the beams over - to the expected supporting walls either side - so that the cellar walls aren't structurally connected to the floor above so that there is controlled movement opportunity (a vertical expansion gap if you will). As you can tell (and why I am here) very much in the inception phase of this idea. Plastic tank - like a large water butt (or even a cheap septic tank) upended and cut - as the impermeable membrane instead of a butyl liner - and then put structural blockwork (STEPOC?) inside? Would this be cheaper? I assume idea would be to get as close to a guarantee of waterproof as possible. I assume you can get square plastic tanks to this dimension. Good idea - have me thinking outside the box about a box 🙂 cheers, -Dean
  8. Hi All, Walking my wife through the NSBRC centre back in Oct we walked past the Spiral Cellar company display and I couldn't block her view 😉. A conversation was had along the lines of "while you are digging the foundations, can't you just dig a bit deeper". Anyway, having initially said "no way we can afford to do that" I then found myself Googling and stumbled across Just about to enter the Build Reg design stage and have SE engaged on the main renovation and extension design. Will certainly needs my SEs input (he has already given a little). Looking at building a 2m x 2m x 2m square basement structurally and then fitting it out as a circle and putting in one of the semi-circular doors. Basic structure would be a Butyl liner, STEPOC blocks walls (probably the 300s) reinforcement bars and concrete. My questions at this stage are: Q1: From a trial hole we know the water table is currently at 1m below ground and we're looking to the cellar to be 2m head height. How would you keep it dry enough to lay the butyl and pour the concrete floor slab. Would we need to drive in some heavy duty steel shuttering but even then will the hole just not fill to the water table level. Is it a race - ie lay the butyl and poor the slab to create some weight to counter the hydroscopic pressure? Q2: related to the above, keep it stable enough (with lower half being below water table) to put the blocks in to then concrete fill them? Would I need to put in internal bracing (horizontal Acroprops or just plain timber bracing) I had actually thought about dropping in some large (2.4m wide) precast, waterproof, concrete inspection chamber units (like these instead of build in STEPC or other labour intensive work. These are expensive and would need craning in but will need a crane for the block and beam units anyway so might be able to coordinate. Dampness and coolness is obviously the objective here (and it is uninhabitable from a building regs perspective which obviously makes it a lot easier/cheaper to build as basements go). As always, thoughts from this group really appreciated. cheers, -Dean
  9. @Roger440 and @Gus Potter thanks so much. I clearly need to read more and bounce ideas of the people here. I'll be back. cheers, -Dean
  10. @PeterW I like the idea of looking at a website called "heritage house" makes me sound like Lord of the Manor. Opening sentence: Ta, -Dean
  11. @Dreadnaught, @Ferdinand and @rh2205 thanks for your comments - although a little scary. Certainly seen the impact of GHG getting in my way re ASHP and EWI that I need. I have good structural local structural engineer and 3C local building control are really helpful. I have a general builder, brickworker and groundworker lined up and access to roofers and first/second fix services (on paper anyway). I'm not doing any of the 'build' myself beyond possibly replacement of existing ground floor rotten timber floor with solid floor and then other demolishing work. Understanding, organising and scheduling is sure to be a challenge. My head is already spinning. I'll keep you all posted. cheers, - Dean
  12. @PeterW - thanks for your reply. EWI - yes, I had considered a french drain myself - a belt and braces approach. Injected DPC a waste of time. Ah ok. Not required as part of mortgage (already have that). Walls are very damp to 1m ish up. By 'internal DPC' do you mean the DPM going up the wall? If this is the case then there would be no real DPC in place - beyond the current compromised one Expansion gap - got you. For concrete you have (if I understand correctly) popped the insulation above the MOT/DPM and below the 'self compacting' and of Self Levelling Screed (SLC?) to level across all sections. Helpful feedback. The Chemical DPC being a waste of time is interesting comment, wonder if that is a general feeling amongst others here. I have no basis for an opinion so all ears. cheers, - Dean
  13. Hi All, My first post here - be gentle with me 😉 I am about to embark on a significant renovation and extension project. I have used an online architect (which are so so but not full service .. but anyway) and a great structural engineer on board. I'm going to managed the trades myself and do a little of the work myself. One of my first tasks and the question here is around removed an existing rotten timber floor, that is 600mm above ground level) and replacing it with a solid floor at ground level. Solid so I can get good UFH system in (and consistent with the extension) and lower so that it is consistent with the intended floor level of the extension. Structural engineer has looked at foundations (1930s semi) and says they have enough depth for me to do that on the basis that a concrete slab would be circa 300mm (50mm hardcore, 100mm slab, 100mm insulation, 50mm screed, blinding and DPM). I'll need to break up the existing oversite concrete that I know is there and excavate out another 250mm say. I'm not going below the level of the existing footings obviously. I'm attaching some diagrams. Q1: any issue with this 'logically' and is my 'circa 300mm' right for current building regs on concrete floor? Q2: current DPC is a badly compromised slate DPC (was checked by a damp specialist and visual inspection tells you all you need to know) and 600mm or so above ground level. I will need to bring the new DPM from under the new concrete slab up the walls to lap into the wall above or below a new chemical DPC? When they say 'lap in' does that mean a shallow horizontal trench (10mm?) cut into the masonry (or mortar) Q3: as the new floor level will be inline with ground level (and below original DPC) are there any other 'damp' concerns and how would I protect against them? The concrete floor will be below ground level - finishing at ground level. You could consider what I am doing as a shallow basement - but water table is a good 1m below where I am. Do I need to 'tank' this more substantially, at least up to 1m above ground level or something? Q4: from the diagram you will see there are 4 sections to the house. The two yellow are timber. The blue are concrete and I need to break that up and replace (lower, insulated, UFH etc). I would ideally like to do them one at a time. I assume this is ok but i need to make sure the DPM of one segment then overlaps (150mm I believe) the next segment. Any issues with segments of concrete? Do I need to tie them together (reinforcement bars?) Finally (thanks for reading this far) Q5: I hope to put in ASHP and will need to run power and flow/return/control cables from what will become a plant room/cupboard. What trunking products would I use to give watertight, airtight solution? Thanks in advance for any advice. cheers, -Dean
  14. Hello BuildHub community, We've just taken on a significant remodel and extension project in central Cambridge and wondering what on earth we've done! Nothing good comes easy I keep reminding myself 🙂 It is a 1930s semi detached house with a large garden. We bought it with full planning approval for a large extension taking it from its small 86sqm to a good size 210sqm. We didn't intend to mess with the approved plans but the more we looked at them while the purchase went through the more we decided on a few small changes and before you know it we had to put in for a full application. We're pending that decision (should be mid Jan 2020) and are confident given it is actually slightly smaller overall and we've built up relationship with the neighbours and believe they have no objections. At the moment I plan on taking main contractor and project manager responsibilities bringing in the trades myself. I also plan on doing some of the demolition and dogs body work myself. I'm a software engineer by trade so hoping I'll be able to handle the home automation and become a source of advice in that domain going forward. Nice to meet you all, thanks in advance for any advice you offer and good luck with any projects you are currently working on. cheers, -Dean