Oldsteel

All good advice, and the blog on the topic is great. I think its all sunk in now. I haven't started the build yet (CIL notice not sent!) so have been assuming everything up to this point is a 'service' such as Architect fees, SE drawings etc. As soon as the build starts - well, ground clearance is the first task - the VAT rules will kick in. I agree the 'certificate' will be useful, per @Bitpipe if I were the contractor having the cert would give me a warm fuzzy feeling I wouldn't draw questions from the VATman. I work in compliance, and if it ain't written down - it never happened ?

I got a quote for half the original quote which was pretty much the same (£500 difference) for Greencoat plx or VMZinc, so I will be going with that. As usual the more quotes you ask for the better, I just took the VMZinc list of installers - which they will send you on request - and contacted all those who were local to me. Most installers will do zinc, copper or steel so you can ask them for comparative quotes. Even if you know nothing about the task in hand - if the quote looks ridiculous it probably is and its worth getting some more! They seemed to vary in recommending the fall, my SE specc'ed 1:80 but they all said that was too level, one said 1:5 which seemed too steep, seems 1:20 is the consensus for a 'flat' roof.

@mvincentd .. walls not turning corners are less stable. This makes sense in the context of our design!

@Sensus I contacted the company referred by your link but it turns out they only do systems for commercial or housing estates. They did however put me on to these guys http://suds-solutions.co.uk who make a hybrid attenuation tank/harvesting solution suitable for domestic and are sending me a quote. I will update this thread with the results. By the way the concrete manhole/hydrobrake is coming in at £4500 excluding installation.

Thanks for all your advice. I like the idea of the combined RW harvesting and attenuation tank, as the drainage engineer had specc'ed the two separately, and considering the cost of the manhole I was going to drop the RW harvesting idea completely. As I have not yet submitted the SuDS report to the council, I will revert to the drainage engineer and ask him about the (less expensive) alternatives suggested here, in particular an attenuation tank, in whatever form suits the site. @Jeremy Harris your comments about the value of the hydrobrake is also well taken, we are halfway down a steep hill and I have no idea whether the houses at the bottom of the hill suffer from flooding due to the arrival of water from further up. Your explanation reassures me this is not simply bureaucracy gone mad!

OK so its a case of reading. The drainage layout diagram was accompanied by 6 charts which described flows vs rainfall, which each of 6 charts describing a period of time ranging from 15 minutes to 600 minutes entitled 'Storm sewer design by the modified rational method'. Needless to say I hadn't studied these in detail. Upon further inspection of each one of these charts I note that the spec of the Hydro-brake appears to be the same: Hydro-Brake Optimum Manhole: 4 DS/PN 1.003. Volume 4.7m3. So, if my calculations are correct with a diameter of 1200mm then the manhole would be 4m deep. A sizeable piece of concrete! So am I stuck with this or is there another way? PS. The design criteria seems to be taking the worst storm in the past 100 years in our area and adding 40% for climate change.

I am at the spec stage of my build (no we haven't turned a sod yet) and my surface water drainage report says, because I am on clay on a sloping site, I can discharge surface water into the stream at the bottom of the site. Sounds simple but just like many other things 'engineers' add huge cost and complicate matters. The drainage engineer has specified a '1500mm hydro brake manhole' halfway down the run to the stream which is intended to restrict the outflow to 2l/sec (two litres per second) 'with a 1.8m design head - a buffer tank in case of storm water'. I have just visited a friend building a house in the next village and he said he had to dig out an area about 1.5m deep 'the size of a small swimming pool' (and it was, he showed me the area which essentially sat underneath the whole area of his back terrace) which he called an 'attenuation tank' which is designed to do the same thing. His was constructed of plastic on a pea shingle bed. Looking online the hydro brake manholes are constructed out of concrete and look to be about 10 feet deep. All in all, this looks very costly either way. Has anyone else come across this and can anyone suggest, erm, ways around it? I suggested to the drainage engineer that we put in a pond to act as the buffer tank as a way to avoid this expensive lump of concrete, but he said we would still need the Hydro Brake in the outflow pipe from the pond! I haven't yet got any quotes for the Hydro Brake but it looks like a single truck to get it to site and a crane to place it, let alone the cost to make it.

Thanks Joe90, of course but forewarned is forearmed!

At 64 I am semi-retired and heading into my last self-build, did one 10 years ago in Ireland but its long enough to forget some of the grief! I started out thinking I would go the PM route and do some of the PMing myself but now leaning towards main contractor and doing bits and pieces myself, as I am happy with electrics (but not certified) and some plumbing work. Like installing a kitchen ,decorating, fitting lighting, home automation etc. What I have learned from my last build is that you can't do enough planning and estimating before you start any work, and you cant research everything to the degree where you have all the answers, so employing professionals you can trust and get along with is critical. Although my last build was largely successful, my target is to make fewer mistakes this time around. @PWS welcome to the forum!

These were not specified by the SE, or the architect. They just popped up in the GW's quote. We have standard block/cavity insulation/stone 300mm wall construction on a 200m2 house. The GW put one at each corner.

We are at the tender stage and our groundworker's quote for putting in the foundations included a £1000 section for the installation of the base plates for 'wind posts'. I asked my structural engineer whether he thought these were necessary and he had no idea what they are! I googled it and it seems they are some kind of steel post to help prevent wind damage? In any event we are not building on a clifftop so can I assume they are not required?

Update on this, we decided to go Rationel for all windows as they are offering triple glazed and we prefer the Alu-clad profile as opposed to pure aluminium. Cost slightly more but we are accepting we need to pay a bit more for better quality. Rationel don't do large alu-frame sliding doors so its another supplier for them (local firm). Having done a fair bit of research its my opinion that pure alu frames are a commodity, window suppliers buy in the extruded aluminium sections and make up the windows by adding the glazed panels. So it pays to shop around as the product is the same (despite what the glossy brochures say).

Is it April 1st?

An interesting thread. I am in the prep stages for a new 200m2 two-storey build, and looking to design my own ASHP and UFH system as the renewable installers around here seem to be super busy and expensive. We have gas in the road but it will cost around 3k to get it in, so will be going all electric, and fossil fuels will only increase in price. I had UFH downstairs and upstairs in my previous build, and needed it in the bathrooms 60% of the year and occasionally in the bedrooms when it got really cold. I am planning to do the same in the current project, but will have to gauge the installation cost. I wouldn't go for radiators upstairs due to the restrictions they introduce. As MVHR was the best thing I did in my last house it's a no-brainer, but not heard before of the heating element. I just wonder though whether having heat blown down into the room - and then sucked out the other side through the extraction vent, is going to be either comfortable or efficient? I get that its low cost though. Solar PV is also a must - as this is our forever house - but I have limited (south facing) roof space - in a conservation area where they are picky about solar arrays. We have land at the back for a ground array, but its a slope facing north-west! There are however possibilities using the terrace to keep a south-facing array from view - if wife will allow? Decisions decisions - that's what self build is all about!

My architect has specified a seamed metal cladding for two flat roofs on our house. He advises me the choice is VMZinc which is the expensive option where it is seamed on-site, or the other option is Euroclad, a pre-seamed product (do they call this standing seam?) which comes in a sheet. I also note that Colourcoat Urban is a similar option to Euroclad and installers have quoted other types, Seamline PLX and Greencoat PLX. As we are still at the drawing stages its an open book and I need to make a decision. Will it still look like a flat roof with a 1:10 fall? What is the ideal construction of the roof - I have joists under and there will be rooflights, and an integral gutter.

Thanks for the info. Will look at Urban Doors also, had a quote for double garage up and over timber doors - about £6k depending on type of timber, choices appear to be cedar, oak or accoya. Probably best to find a best match with a bespoke oak front door - certainly wont be paying £15-20k!

@Dan Feist we are at exact same phase as you. I have pretty much discounted the PM route due to the difficulty of finding any suitable candidates. Lots of good builders around and available it seems, all expressing interest in our project for a start next year. BR drawings will be ready soon and I plan to send them to an estimating service to get benchmark costs to use when obtaining builders quotes. We have already costed big ticket items such as windows, doors and heating system. Groundworks will be a significant part of our project as we are re-aligning the site boundary and the site is sloping in parts, so our options right now are: Whole build - main contractor. Cost likely to be a big issue here. Separate groundworks contractor then main contractor for the build As above but have the builder put up the shell and then use subbies for the rest. I can help out here as I have an engineering background. Having done a previous build our main aim now is to plan, plan and plan before starting any work! Discharging planning conditions right now.

Thanks @PeterW we had looked at these guys but didn't spot the infill option. Will defo give them a call.

Anyone know if there are suppliers of matching garage and front doors in solid oak? The garage doors need to look like barn doors but up and over electrically controlled. Front door traditional with a single small window.

We are looking at Rationel alu-clad windows for our house and as far as I know they always work through local agents. Our local supplier quoted for Rationel throughout but said the 7m 6-panel aluminium sliding doors would come from a different supplier. So we have already accepted that the feature window will have to come from a different supplier so started to look around and found cheaper alternatives. Furthermore, all the windows on the front and sides of the house are standard sizes, while the rear are bespoke. We found Rationel are not competitive for the standard size windows, but are the best priced for the bespoke sizes apart from the sliding doors. So it is likely we will have three different suppliers, which is not ideal (and I note the comments above about glass) but when the difference is measured in £000s we will make it work. Look also at costs for fitting, these vary a huge amount between suppliers. Supply and fit is the way to go so the supplier takes 100% responsibility for the job. I have heard too many stories where we end up 'piggy in the middle' between the window supplier and the builder when things go wrong, as it seems they often do where windows are concerned.

Yes, I will call the planners re the CIL commencement, when I can get them the answer the phone ?. What is the definition of 'commencement', especially when the conditions state 'prior to commencement .... SuDS .. BRE365 .. etc'

Thanks @nod I like the throwaway 'building one house' line ?. Glad to hear I am on the right track though! @LA3222 that's my plan too, its a good starting point.

I am at the preparation stages for a 4 bed detached in the Cotswolds. Discharging planning conditions, getting initial quotes for the big items, having the BR drawings done and lots of conversations! My plan is to send the BR drawings to an estimating service to get benchmark cost and some kind of idea of the cost (which of course will be more than I budgeted for). The house is 200m2 on a sloping site. I have read many of the threads here and can see the benefits of retaining a good QS throughout the project. So should I get a 'Bill of Quantities' from a QS at this stage with the advantage of developing an ongoing relationship, or pay my £150-£250 fee for the online service and dispense with the QS? Understand services such as HBXL are often used by builders to do quotes anyway.

I am at a similar stage in my project close to you in Gloucestershire so this thread is very useful to me too! I have a planning condition that states: Prior to the commencement of development, a full surface water drainage scheme shall be submitted to and approved in writing by the Local Planning Authority. The scheme shall include details of the size, position and construction of the drainage scheme and results of soakage tests carried out at the site to demonstrate the infiltration rate. Three tests should be carried out for each soakage pit as per BRE 365 with the lowest infiltration rate (expressed in m/s) used for design. The development shall be carried out in accordance with the approved details prior to the first occupation of the development hereby approved. Is your requirement a planning condition? I cant see any way around getting a contractor in to do this. My building regs guy could do the drawing (at extra cost no doubt) , I could get the GW guy to dig the pits but all this would require oversight by someone with BRE365 knowledge, and then there is the final report. We are on a sloping site, no sign of clay and a stream runs across the bottom of the site. So as my BR guy pointed out 'it's a piece of cake'. But I still have to discharge the planning condition ..... hence my question!

Thanks all for your advice - this has answered all my questions! And of course as I read on other threads the original invoice for labour must be zero-rated, as these cannot form part of a reclaim. I will likely write out a 'certificate' like the one from JS Harris just in case!