WestcountryWonderer

Yes, I think this is correct. I think the systems have to have a bit of thought put into them to avoid this. On the other hand as you say, PV either gets used for other loads once the cylinder is hot, or worst case just goes back into the grid

I would tend to agree with you (in my also limeted knowledge) in it's basic form, solar thermal is a pump and a valve and an expansion vessle and two heat exchangers - on the roof and the cyliner. aside from the pump and valve (which is no different than the central heating systems we all have), nothing else moves. Happy to be corrected here. My only thought is that PV has no moving parts at all, and the systems whilest containing complicated electronics, are failry well developed to be reliable. In my mind it comes down to which is more efficiant, and most cost effective.

Yes That is my understanding. And again, I'd do an in roof install as we're re-roofing at the same time so the panels wouldn't protrude past the existing roofline. However we do have some listed buildings nearby (although ours isn't) And the planning officer I was speaking to did make a comment about adding them into updated drawings (as we're looking to make a non-material ammendment elsewhere) but I never managed to get him to clarify his comment as I don't really want to back myself into having them by putting them on the drawings when there are a lot of factors that could affect fitting them - money/DNO approval etc etc. Any way. A bit of a tangent there!

Thanks for the comments. Additional PV is the other option I have so that might be the better route. I have 6.5kWp (on a 3 phase supply so still within the 3.6kWp per phase) split 50:50 on east/west facing roofs. I can potentially get some more panels on a south facing roof when we do the extension. Just debating if the council planning will have anything to say if the PV (or ST) goes on at the same time as doing the extension works. I'll go and trawl through the PV part of the forum next then!

I'm looking into fitting solar thermal when we build our extension. I already have PV which I am in the process of diverting to the immersion heater but also considering batteries so wondering if solar thermal as well would be a good boost to the hot water and allow the morning PV to put some charge back into the battery again. I remeber finding a supplier who was recomended for teh DIY world, good quality kit but happy to deal with you and me as well as trades which a lot of the big auppliers aren't so helpful if youre not trade. Does anyone recomend anywhere for supply but also for information about the set up etc? Looking to get an upderstanding for how the system is installed as well before I commit to a definate yes. I'm looking for in roof panels so presumably flat panels if that makes any difference to recomendations?

Good afternoon. I'm part way though getting planning permission for a new garage, things are looking a little more hopefull now so I'm back to thinking about the details again... I'm planning to build using Nudura ICF and could do with some thoughts/words of wisdom about the garage door threashold details. This is a large garage (9.5m x 7m) so will come under building regs,. It's not heated, just insulated to keep it reasonably comfortable for a garage/workshop for myself. So far I'm planning to use Geocell recycled glass for the subbase as that will give insulation and a solid base in one product. And then I'm less likely to worry about how stable EPS or smilar would be for under a garage floor (I'm building to allow fitting a two post lift eventually). On top of that is going to be a 100mm concrete slab, then build the ICF walls to form the perimeter, then once the walls ect are finished, a second 100mm deep concrete slab over the top of the first. The reason being the first will give a solid surface to fix the ICF supports to but then I want a nice smooth powerfloated finish for the garage floor without any holes in it that need filling. A litte over-engineered perhaps but unless there is any glaring issues people can see with it, I want the best finish that I can achieve. Originally I was thinking of using the Nudura under the garage door threashold, up to the top of the first 100mm slab, then when the second slab goes in, having that flow through the door opening to create the threshold, with a 30-40mm step in it so the door closes onto the lower part to help it seal and keep out any driven rain. I could reinforce the step with a bit of steal angle (galve, painted etc) if needed. I started wondering about how best to finishe the DMP. Should I just run it out through the door and finish it at the edge of the slab, or should it be finished some other way? Another option would be to use curb stones along the front of the slab to help reinforce it against wheels 'tearing' at the edge and also act in a slightly saecreficial way. Or are there any better ideas?? Part of the reason for using the nudura under the door opening was to reduce any thermal bridging, I know the room isnt heated, but I figured that every little helps. Is it really much of a big deal? Am I better just having the concrete slab going down to the foundation level and so making the threshold stronger still? I'm planning an insulated sectional garage door from Securoglide, to be fitted in the reveals rather than on the inside face of the walls. On a side note, the geocell glass supplier recomend using a geotextile under for the DMP, but in my mind that wont keep damp out, so surely that should be a proper DMP sheeting? I've attached a couple of PDFs that hopefully help with my explanation. Any thoughts or comments would be most helpfull. Many thanks!! GARAGE DOOR DETAIL.pdf TYPICAL WALL & FLOOR DETAIL.pdf

Sorry I wasn't very clear with the background to this - it was the previous owners who got the planning permission and for some reason they/whoever did the survey for the drawings appearently did not lift the lid of the manhole. When I get a minute to do that, it should be prety clear as everything is within aabout 1m or less of said manhole. What I'm wondering is if building control will allow existing rainwater connections to the sewer main to remain as that when the extension work is completed, or will with insist that all rainwater is diverted to the soakaway. If the current drain situation isn't clear when I open up the manhole and/or building control are likely to allow combined rainwater and sererage to remain, they yes, a camera survey will ineed be worth it.

We only bought the place at the beginning of the year and the drainage survey only showed a combined sewer, plus its a small rural village and a lot of the houses are 100s of years old rather than 10s. So I very much doubt there'd be a separate sewer hiding somewhere. The square meterage is there and the ground drains well enough for a soakaway that will cope with the whole roof, it's just going to be a bit convoluted to get there from the front

Not withstanding the old addage about assumptions... My extension planning drawings show that the current soil stack, kitchen waste pipe and rainwater pipe are "assumed to be combined and connected to the sewer" or words to that effect. Most likely they are assuming that the combining is done under the manhole cover that's next to them all (why they made the assumption and didnt just lift the lid up is beyond me, but that's getting off topic!) If this assumption turns out to be true, would building control likely allow them to remain combined albeing probably with a new inspection chamber? or would they insist that the rainwater gets diverted to a soakaway? We already have a soakaway shown in the back garden for the rear roof and at a push it would be possible to divert the front roof to that, but it would be a bit of a pain that would be nice to avoid if I can. Not to mention convoluted and long which opens up more chance of blockages vs a nice short run of around 1m... Am I also right in thinking that if they are combined, they must do the actual combining in an inspection chamber and not tee'd into the soil stack itself at a low (under ground) level? Both instances having a trap at the bottom of the rain water pipe.

That is a very comprehensive list, and is what I was aiming to achieve with my last house (renovation not build) but I got a bit lost along the way. A couple of thoughts though. To save running telephone wire and cat cables, telephone can utilise the cat cables. The down side to that is cat5/6 is slightly more expensive than telephone wire. Up side being that one cable can do either/or job. Long hdmi cables are OK, but if you're burying cables and/or running them any great distance you'd be better off looking at hdmi over cat. Again, it increases the cost slightly, but the reliability and quality will be better. You can do similar for audio too.

I'd run as many cables as you can. At this stage it's easier to put more in than it is later down the line. If you can, and you think that you'll have a lot of them, pick a central location to run all of your CAT cables to and put a hub/switch there. Ideally near where the phone line comes in to out the router there as well. Also think about tvs etc all being able to connect to the internet now a days. In an ideal world, anything that is in a fixed location should be hard wired to the Internet. The less you have on WiFi, the better it will perform for things that have to be on it. Are you likely to have cctv? If not now, in the future? They'll want cat cables too. For terrestrial TV signals you can do the same, pick a central location and use a splitter to send the signal to anywhere and everywhere you want to. Sky gets a little more tricky as I believe that you can only have a limited number of tvs per sky box (I've never had it though so could be corrected on that!) As for cable segregation, as far as possible is always best, but 100mm should be ample. The reality is that in 'normal' domestic conditions you're unlikely to notice much of a difference even if you ran signal and power side by side.

The next question that has sprung to mind on this topic is that I have a rain water outlet that is noted as 'assumed' to be connected to a combined sewer via a manhole (there is a soil stack running next to it.) I suspect that the reality is that the rain water pipe just goes into a hole in the ground rather than anywhere meaningfull. Am I right to assume that I wouldn't get away with reinstating this and actually running it into the combined sewer if it isn't already? What about it it turns out that it does currently go into the sewer, can I reinstate it to the sewer then? And I guess that I am also right to assume that if I move the rain water outlet from the front roof which currently discharges into the road (and therefore eventually the sewer) to the other end of the house, then this will also not be allowed to discharge into the combined sewer? And must go to the new soakaway?

That is interesting about insurance and not something I had really thought that much about. Although it might be me being a little neigheve but my house insurance doesn't cover any item over 2k unless it's been listed anyway. so I'm not sure what the difference would be. the house insurance is due soon so I'll give them a call to see what they have to say

I hadn't thought about that if I'm honest, but part of the reason for thinking about SIPS is that I seem to remember a national homebuilding webinar wherre the SIPS manufacturer went to great lengths to ephesise that they are classified as 'traditional building method' for insurance etc. i.e. they have certificates etc etc and not just someone has got a pile of timber and nailed it together. I hadn't considered ICF but I will look into it. Especially as I've just seen a social media post from the architecht who's coming to look next week that she has just done a training day with an ICF supplier... This is also where I'm thnking that plasterboard and skimed walls and ceiling are the only option internally. With any joints sealed with firee proof silicone. Thanks for that, what size timbers did you use there? and were the trusses manufacturerd or did you make them on site? I want to keep the roof as low as possible to help with not upsetting neighbours and not blocking out too much sun from my garden. But it's good to hear that someone has done a 7m span as that was one area I wondered if I'd come unstuck in. The main reasons for avoiding block and brick is the time it will take for me to build it. Lots of food for though from here though so thank you, exactly what I was after with this post!

Thanks. That looks very nice! I'm aiming for 2.5m clearance through the door (my Land rover is just over 2.3 high so need that and little spare for comfort!). Trusses are possibly an option for mine, but not sure if I'd spend more money getting them calculated and made than I would just stick building or going for SIPS which would be easier to keep the clearance. The insulation for me is partly having to comply with BR but also partly trying to keep a fairly stable temp summer and winter while also keeping the dampnesss out to stop things rusting! aread wise I could get in under PD as the garden would be big enough. But the height would prevent that I think and the proximity to the boundary definately prevents it. I cant afford to move it further off the bournary as that will be too restrictive so planning permission is the only option. Hence having an architecht take a look

Here is what I'm hope to achieve, any comments or suggestions will be most welcome. I have an architecht coming out next week to have look at feasibility for planning etc. but I want to do as much of this myself (i.e. all of it) so trying to get advice and ideas from as many sources as possible! There is curretnly a single garage around 6m x 3m, 3.5m high to the ridge (2.5 to the eves), single skin block. I want to knock it down and replace with a much larger version, 7m x 10m, keeping to around 3.5m to the ridge but I'd like to achieve around 3m ceiling height inside to allow for a car lift in the future. For that area I know it will need to comply with building regs and I'm planning either stick built timber frame or SIPS to maximise internal floor space for overall footprint and for speed/ease of doing it all myself. The biggest constraint I currently have is that it will have to be around 300mm from the boudary which is where I think SIPS might be a better choice as they'll meet the fireproof requirement without much of a fight? The second biggest constraint I think is the spans as I'd like to keep it totally open inside to no pillars in the middle of the place to support roofs. Not sure if this is being a bit too optomistic though. Foundations: Would I likely need trench fill foundations for something of this size with timber frame or SIPS? Or would I likely get away with raft foundations? What's the score for aproval of this, is it purely a structural engineer job? Floor slab will need to be around 200mm deep reinforced concrete to allow a lift to be fitted later. This is where I'm thinking that trench foundations might be simpler. Pour the foundations, a course or two of blocks then infill the perimeter for the floor? I am thinking about GEOCELL floam glass for under the slab, it is spec'd for the extension we have planning for and should kill two birds with one stone. Has anyone used it before? Or am I better going for a more traditional MOT then celotex then slab? Walls: I have looked at Eco SIPS, can anyone recomend any others? I was thnking their 119mm panel build up from the ouside as follows: UPVc wood effect cladding (fibre cement on the boundary wall if required for BR)>38mm vertical battons>breather membrane>SIPS panel>vapour control layer>25mm batton>plasterboard & skim. Do I have the membrane & VCL the right side of the battons? Being a garage I'd like something more substancial than plasterboard to fix 'stuff' to, would OSB or ply meet building regs or would it have to be plasterboard? If I went for stick build timber it would be: UPVc wood effect cladding (fibre cement on the boundary wall if required for BR)>38mm vertical battons>breather membrane>25mm horizontal battons with 25mm celotex between>100x50 studs at 400mm centres with 100mm cellotex fill>11mm OSB>vapour control layer>25mm batton>plasterboard & skim. Same questions for this option and do I need a sheet of OSB on the outside as well? Roof: I'm thinking either EPDM or square box sheeting? either 144mm SIPS or stick built again. Pretty much the same build up as the walls for both options. Aside from that I'm thinking of a couple windows in one wall, a pedestrian door and a roller door. I like the idea of a couple of clear panels in the roof to let a little light in but not sure if this will over complicate it for not much benefit. The only other thing that I am not sure either way on at the minute is air circulation. would it be worth fitting a cheap single room MVHR unit to keep some air flow and stop any damp stagnent air sticking in there? Something like this: https://www.extractorfanworld.co.uk/vent-axia-435004-hr100rs-single-room-heat-recovery-unit---suspended-ceilings-2726-p.asp Or is that a bit over kill? I'm hoping to get some more detail and skitches together next week, but as an outline, what do people think? SIPS might just be winning in my mind as although they'll be a little more expensive, it will be quicker and more straight forward...

The other thing that has just sprung to mind is that I assume that drainage is something that building control will be quite interested in? How much are they likely to want to see? I know that each inspector will be slightly different, but are they likely to want to see all the trenches open with pipework before they are filled? How about soakaways, are they likely to want to see that all in place before being covered in?

That all makes sense! Nothing like mother nature to throw a spanner in the works once you've meticulously planned what is suppsed to happen. Is there anything particular so far that might be pushing my luck? I'm really at the beinging of a long journey of learning here. Happily as an engineer alot seems quite logical, but that also often leads to over engineering job and not being able to see the wood for the trees. I will indeed report back as things progress. It will be a long process though! And there'll be a lot of other questions on many topics along the way!

Indeed it is! Although I often reach the point where planning any further becomes more counter effective than just getting on with the job...

The current updated plan then is looking like 110mm drain dug into the drive 600 ish deep to take the gutter outlets into a rain water tank then the outlet of that into the soakaway via a silt trap. French drain also along the drive, tee'd into the chamber for the patio drains and then directly into the silt trap and then soakaway. If I put any channel drain along the house/drive edge this would also drop into this run and so bypass the tank. Use the rain water tank only for garden use (and probably add a pump at a later date to reduce the initial cost). I'm figuring that the french drain would also want to be down around 600mm as it would be in the drive and any shallower than that would probably need some form of concrete capping over the top. Does that sound about right?

This is one other through I have been considering. I'd like to drop the drive level down to first floor level or slightly below to awoid any dampness in the ground tracking through to cause damp in the wall. In doing this though, I might end up with a drive that actually slopes towards the house wall which would be more detrimental than leaving the ground level as it is... If that turns out to be the case ( I need to get out and do some actual measurements) then I either leave the ground level slightly higher outside and do the best I can with it. Or I purposfully make the drve slope towards the house to get the ground level lower and put an aco drain along the house (set away slightly) to catch any runoff. This does though run the risk that in heavy rain, the channel would be overwealmed and I could cause more damage than good. Also it means even more digging and planning drains....

That was the general feeling I had RE the French drain into rain water harvesting. Thought I'd get some second opinions though as runing it to the soakaway will be a little more complicated/expensive. Makes perfect sense though! And I need a second of drainage going directly to the soakaway anyway so that will just tee into it. I think I've read your posts about the IBCs (I've been going quite a bit of reading up on RWH the past few days) my original plan was IBCs behind the garage and gravity feeding a tap for the garden, but a buried tank will be much better for many reasons. Unfortunately I think if I can make the costs work out sensibly then the extra cost of a tank will outweigh the hassle of burying IBCs. Then with a proper tank I can pump it for WCs in the house as well as the garden/garage tap. Lots to think about and cost up!

Thanks. I can imagine there are a few 'interpretations' for the various depths in the building regs... If I can get away with 600 deep then it means a little less digging and back filling to do! The plans have a patio with a gully and aco drains which will have to bypass the rainwater harvesting if I do fit it, so the safest bet is probably to just take the French drain to that (again, if I do out one in)

Good evening. Bear with me on this one, I might just be over complicating the situation... My current thought process which I'm trying to figure out surrounds dranage and rainwater etc. I might be thinking too in depth given that this isn't going to be happening until next year at the earliest but like that song that you can't get out of your head, I've got this currently stuck in mine! I have planning for an extension on the house, but I also want to knock down and re build the garage. The planning for the extension requires a soakaway to be fitted (relatively straight forward...) and the garage will require the same, so two birds with one stone. The boss also wants a big veg garden so I am looking at if I can justity rainwater harvesting. Question 1: Would fitting a rainwater harvisting tank allow for a smaller soakaway? If so, how do I figure out the ammended soakaway size? Next, the drive will eventually be either gravel or possibly some form of permiable surface (I'd rather have something permiable to avoid complicating the dranage further than I am currently thinking, but I would like something more solid and stable than gravel. But that's going to be a discussion for another day as this will be the bitter end of the project and as we're yet to start, who knows when the end will be! I digress...) I am looking to run a 110mm drain in a trench down the length of the drive and into the garden, then onto the soakaway (and perhaps rainwater tank) to collect the water from the front & side roofs. Question 2: Does a drive count as a 'light road' and so require 900mm covering or is it more 'Garden' so can it be 600mm covering? I suspect the former just to make my digging more difficult. Finally, the house is 1600s ish so likely to be no or very little foundations, it also has a little damp in the wall along the drive. The dirve is slightly higher than the inside floor level in places, and I hope to reduce this to floor level where I can in the long run, but this might not be practical. So I'm considering putting a french drain in the drive, around 1m way from the house wall so as to not be too close to the probable lack of foundations, but hopefully help with some of the damp. Question 3a: What are peopls thoughts on a french drain in a dive way? What depth should I be thinking about digging this to? Question 3b: I know I can't put surface water or water from an open Aco type drain into a rainwater harvesting tank, but can a french drain be directed into one if the trench is lined with geotextile etc? I'm leaning towards 'No' on this as it might pick up some silt. On the other hand I'm thinking that with a lined trench this should be minimal and adding a silt trap of some form at the end of the french drain should catch the last of the silt so it should be ok... That is enough of my waffel for now I suspect, hopefully I've made some sense there. Thanks!

Thanks for that, I'll ass them to the list of people to call as things progress!