MikeSharp01

I am going over to Maidstone at the weekend to 'build it live' to close the deal on our windows and happy to say hi to any others here who are going down, PM me if up for a face to face, coffee, beer, sandwich.

I am sure that many will realise that self building is not for them - self building is not for the feint hearted - well you don't see them on here do you, but some will be prompted to give it a look and then give it a go. Like most of us here we are not trying to make a profit, we have targetted our build cost, everything, at the average selling price for similar sized houses in the location we are building. Although the other half got a shock the other day when she spotted that the house opposite, slightly smaller than our build, is up for £100K above the average selling price. We have a 10 year view and have worked out energy, servicing and house price fluctuations in our model which helps us be confident that we will both have the home we want at a cost we can afford in the medium term - our offspring will get the benefit if there is any. We are targetting £1200 m2 and the budget is running out just below this on the progress / spend line, we are doing as much of the work as we can ourselves to manage cost and ensure quality. Budget is everything as you might expect and if you are not up for some of the heavy lifting (not literally) you can expect to pay top dollar. @JSHarrisI think there are many ways to skin a cat in terms of how you apportion that budget. We are, in effect stick building, so have an on board SE - but I guess / cannot recall from your blog, you had your SE work done as part of the timber frame package. We don't have the aesthetic skills to think through a properly proportioned building within the envelope we have so chose to use an architect (the full RIBA package as far as detailed drawings). We will always live in a one off architect designed home and that does have a market value albeit indeterminate, I am not sure we have direct value for money but the 10% (Architect and SE) of the cash budget is going to be about it on our build. So we have those two but won't need spend in other places, we have no difficult ground (yet), we have mains water, sewage, gas and a PME mains supply (could have three phase if we wanted as its on the pole that is on our land) so we saved there. I have costed my time into the budget using a mixed mode formula - I could be earning elsewhere if I wished to but luckily don't need to, so it is part of the build cost. I did wok out a formula to cost each of the trades against my time and my estimated efficiency against a full time pro but it got silly / complicated so I abandoned it and just put in a figure based on a simple analysis of the housebuilders bible.

Tend to agree Jeremy but there may, just may, be a campaigning angle to this series, unlike GD, where Charlie, or the producers, actually think that they can support the self build movement while making entertaining TV. As I think I have said elsewhere most, if not all, such programmes have a nugget or two of interest for the observant viewer - and this week for me it was the house they visited in Glasgow and the glazing in the main featured house. You do have to learn to see past the hype and make a realistic assessment of the cost / value see-saw.

Many thanks Peter that looks great let's see what the other half thinks.

Interesting point! I to have buried traps in our design and the traps are rubber olive and nut joints. I wasn't worried about the joints as we have exactly the same set up here in our ground floor wet room and it went in 12 years back and so far no problems.

I haven't got Rationel windows, did you mean Rehau? Sorry Peter, my mistake. A pic of the corner without mitre is all I am looking for I guess if Rehau can do it they all can.

Hmm specification seems rather vague. Does he want a love seat - sitting offset side by side looking in opposite directions - its all about eye contact, a seat he can love, a seat he can make love on / around / over or none of the above or all of the above.

Welcome and what an amazing opportunity. We are stuck in the South East but spend about 6 weeks a year in Scotland which we love. Best of luck and I look forward to seeing your progress.

Do you have any pictures of the internals of your so treated Rationel windows? Think the other half might be coming around!

Just spoke to other half and suggested a commission - she is off surfing.

Adusted spacing is standard roofing practice for tiles, even the interlocking tiles have built in wriggle room. Roofers do it in both, sometimes three planes.

Agree but wood has a lot less embodied energy and it looks like we won't have Ali clad so best possible on that aspect. However great chunks of the build has Ali facias so the windows reduce it not eliminate it! Anyway we shall see what we shall see at the weekend!?

Love the idea of stained glass on the two obscured glass windows required as a planning condition of our build. They have specified a grade but I recon the BCO would be happy with a good stained glass. It will have to be ' attached' somehow to the passive house windows but I can see a way to achieve that.

From my perspective the mitre thing is close to pure prejudice on my other halves part but there are a couple of other reasons. She feels that UPVC has too much environmental impact and the sections can be deeper. I am working on it. Off to build it live in Maidstone on the weekend where we will make our final decision.

Brilliant, might run this past the other half and she if she might accept it as it would bring Rationel to the front of the price queue provided the filling was not too great a cost.

We are at the point of choosing now and my other half won't have UPVC as the corner joining (mitre) on the inside offends her so we have to have wood or Ali on the inside, one thing to remember about UPVC is that you can paint it with the correct prep and paint on the inside if you don't like white, Sandtex (and many others) have a primer on top of which you can put any of their colours you like. This would be the cheapest option, although painting might be fiddly on the internal glazing bars etc, and you can change the colours as you please. If we didn't mind the the mitre it would have been the way we went as you can have Internorm (studio), not much doubt about the, quality and any internal colour. Of course you could go for Rationel at a lower price and still have the internal colour over white.

Upvc / Ali clad wad about 10% cheaper than wood / ali on our Internorm quote. The only difference is the internal finish and slight construction differences. Rationel were cheaper, GBS (Green Building Store) do wood only but still offer wood internal finishes I think.

Yes but is he still; alive / complete / uninjured / married / without 'scared for life' kids .....

Welcome. Sounds like a fun project.

Yes that is an idea, some thoughts from me - needs refining I suspect. Just get a USB / blue tooth controlled motor inverter that will set the speed and provide all the current / power feedback you will need. Then two pressure transducers in and out, Once the pressure difference is reached back off the power (speed) and until it holds steady then measure the airfow. Thinking about it you might be able to calibrate it by running the fan into a sealed, guaranteed, box - will probably need to be quite large or turbulence might be a problem, then measure the pressure difference and get the fan power back to stable desired pressure difference then take the power reading. If the house is sealed once the pressure difference is reached the difference from the power reading taken above will be proportional to the leak area. If you drill holes in the sealed box you can see just how big your leaks are by matching the power readings for known hole sizes (areas). (PVT so keep the temperature stable.)

So, if you keep it clean - filtered, it won't need cleaning? I wonder what the implications are for the system if the filters reduce the flow and you cannot balance supply / extract without decreasing the supply area to match the resistance of the filters, will this not lead to an increase in overall flow rate, and associated fan speed to achieve the air changes and won't that increase running cost and noise to the point where cleaning is a better option. Just wondering - too much coffee - still hyper!

Sorry Joe, just got to this in a break from bending Rebar! Yes its the joint at the top that is the problem. I was going to CNC cut several plates to go either side of the web to create the joint but its impossible to work out where the failure will be, although destructive testing might get to it, because the web is OSB the plates are Ply and the nails are nails, as the load is applied eventually the plate will start to turn, in trying to keep things in place, and will start to load up the flanges at the foot & head of the joist and the joint between the web and the flanges is not designed, or even contemplated, to be loaded up in this way, steel joists are all one material and so don't have a problem. If you glue the plates then the failure moves to the web itself just below the end of the plate because, essentially, of the turning action and the point loads it induces in the web and the associated flanges. In the end after looking at this for a long time, I was at first reluctant to believe the joist companies, and running my thinking past academic structural engineers of my aquaintance I gave up and accepted the ridge beam - ho hum. It adds about £500 to the roof cost for us.

Hi Joe. We had the same problem as we originally specified a I-joist portal frame - essentially they cannot calculate the shear forces in the joiner plate against the web - or rather they can but the manufacturing method would be critical and the joists are not built to be reliably calculated in this mode. Both the joist companies looked at and the SE and came to the same conclusion. I have done some tests and I tend to agree that its hard to get a reliable strength. Someone sent me off to find a steel portal structure that did not extend the beam depth in the centre down to take account of the 'flattening forces' and I couldn't find one, so have to agree with today's technology it cannot be done in I-joists. Putting in a ridge beam means that the load is not transferred across the roof but down onto the the beam in the middle and down at the walls. In a traditional trussed rafter roof the whole thing is trying to flatten out and its stopping that where the ridge joint and associated calculation comes in. Add a ridge beam, itself supported by uprights somewhere, supporting the ridge and that problem goes away. (Edit: Although there is still a small component of force pushing the wall out)

Try polyurethane adhesives. I have Stuck cement roof tiles to EPS., to do the same job you are doing and that works plus I have stuck upvc, roughened the upvc first, to wood with the same stuff so it should work as it sticks to both.

You probably need to budget around £25K @£1000 per square meter but could go up or down. UP if you have difficult ground, employ an architect, Structural Engineer and include additional kitchen / bathroom areas. DOWN if you have easy ground, can design it yourself, can do a lot of the work yourself (WAY DOWN) and its just an open space with only electric points and simple lighting. Your actual location will also be a factor.