SimonD

I last used Wykabor 10.1 to treat approx. 40 meters of glulam ring beams and a load of untreated CLS. Here's the data sheet Interestingly it does say: However I do suspect this only applies to wet application, not once the product has dried after application. Possibly worth a call to their technical department. HTH.

Kind of... grooves up are the traditional way, grooves down are an alternative, but the important detail is in which to use depending on the cupping of the boards once they're installed. If installed so the top board cups out, meaning water will run towards the edge, then the groove is outwards. If installed so that cupping is prevented, the groove goes to the inside to prevent capillary action under the boards. Personally, I do wonder about the obsession with screws. Nails are, believe it or not, absolutely fine - tried and tested. It's a great site for details, a lot of it builders here in the UK could learn from for timber frame detailing.

I think it's sensible to use the existing floor structure and to retrofit insulation. Depending on joist depth you can pretty much select the insulation material of your choice, but if you're lacking depth then Kingspan stuff is probably a better choice even if it's a pain to install and detail properly, particularly in retrofit. Above the new floor insulation you should also concentrate on making it air and vapour tight. Either chipboard, or osb subfloor would work well above. If tiling, then it's better to use a tile board - No More Ply sells a 6mm board for this purpose. With floor insulated and timber subfloor your floor will feel warmer, but ceramic tiles are conductors so will feel cool underfoot without the boost of underfloor heating. However, this coolness doesn't tend to feel uncomfortable. The resilience of the timber floor structure actually adds to the comfort of the floor. Here's a great resource about suspended timber floor and insulation. Covers pretty much everything you need to know and maybe more Suspended Timber Ground floors HTH

I haven't looked at the link but that's about right - that is what plinth insulation is. Basic buildup illlustration, from ground: gravel, plinth insulation, expanding foam tape on top of plinth insulation, starter rail at dpc, then your normal ewi. Plinth insulation thickness should indeed be reduced. IIRC, i read a rule of thumb figure that it's thickness is determined by either 75% of thickness of ewi or 75% of the ewi thermal insulation figure - can't remember which right now and don't have acces to the relevant paperwork right now. Either way you get a drip at the bottom of your main ewi at dpc.

Why? Have you expained the ramifications and the difference in product? I've usually found that a quick conversation along the lines of cold bridge = condensatoin = black mold on those lovely new deep window cills, sorts the issue out very quickly! Otherwise, just make an executive decision...

Yes, that's with render finished.

I'd approach this very carefully. EWI takes a lot of care to detail properly and I'd be surprised if a general builder knew the detailing requirements - it's bad enoug finding an ewi company that really knows what they're doing. I think the prices you've been quoted might be on the cheap side. Last time I got a complete figure it worked out to about £75/m2 plus VAT by an EWI company. This was 4 - 5 years ago. Recent figures I've heard from other it's been up to £100 labour and materials. Some of the things the consider: Old substrates where old render has been removed may need a levelling coat before installing the EWI to avoid excessive voids behind that can lead to unwanted convection. Windows and other openings are a bit of a pain as you need to ensure no joins are in line with the corners, so it's a bit like a game of tetris. Then you have the detailing around the reveals that need to be done with care to prevent cracking and water ingress. If your reveals are to be 40mm as per your insulation thickness, you're going to struggle to include both a corner bead and apu rail - the rail that seals the render and ewi against the window frame - so you will have to look at some alternative detail as just using silicon is not best practise). Are you having plinth insulation installed below dpc? If so, what is the cost of the usually specced xps, rendering and ground detail? How is the builder suggesting you deal with service openings and runs - e.g. soil pipe, guttering, waste pipes, gas/electricity meter box, and any phone lines/electricity cables. And that's just the beginning. Also keep in mind that Kooltherm is not vapour permeable so you'll need a careful look at moisture and condensation management to the interior of your walls. EPS would be better as it's considered to be semi-permeable, so better than none. Rockwool ewi possibly even better on this front. Anyone looked at your condensation risk for your proposed ewi? Overall, I think you'd be better off finding a dedicated EWI installer to do the whole job including the final render. That way you'll be more likely to also qualifiy for the manufacturers system guarantee too - whatever that may be worth ? At present you run the risk of multiple parties blaming each other if there's a problem down the line - not unheard of with poorly installed thin coat EWI. Sorry if I've put the cat amongst the proverbial...

Thanks, that's helpful. Unfortunately, I can't go and test right now as I'm here in England and the heat pump is in my mother's house in Sweden. Unfortunately the installer seems pretty rubbish and is fobbing her off while the manufacturer has been pretty good. Manufacturer is having a word with installer.... I think that one major problem is they've focussed only on the heat pump, not looking at the whole system.

Especially when it's -3 in January! Not sure there's anything worse than a day handling frozen steel.

It's a 3 day course giving participants an overview of the self-build process. Starting with funding & finance, finding landing, design, building & construction methods, planning permission, building regs, blah blah. Day 3 is 'eco' s tuff and it's £395. TBH, I don't think this will cover the areas in any such detail to give him an opportunity to find out what he's interested in. It'll only really touch the surface of what you need to know with a self-build too. Personally I'd say the best suggestions so far are for him to find builders and/or trades and then shadow them for a while, or go out and buy a small project low risk project that can be used to gain some experience and learn what it's all about. The other more far out suggestion would be for him to quit his job in the city and get a job as an estate agent for a while. Laugh or scoff, but that'll give him access to the market, get to know trades, and find potential properties and be able to sell them. I know someone who did this and made a mint as a property developer after learning the market.

A recent discussion with a Swedish heat pump manufacturer re the problem I mentioned above, said that compressor should not be regularly tripping out at the high pressure threshold as that indicates a problem within the system and will cause excess wear on the compressor system (this what was happening in the example I mentioned, hence premature wear of three compressors). Admittedly this is on a geothermal heatpump rather than air source, so may be a diffierent issue. Now, I can only take their word for it as I'm no expert at this kind of thing so very happy to understand more.

ASHP isn't just about chucking in the pump and cylinder though is it? You've also got to design and commision the whole system so that it all functions correctly. I know someone who paid a lot of money for a heatpump installation and because something was wrong, it's burned through 3 compressors and now requires a whole new heatpump as replacement.

I'm wondering from this whether he actually wants to be a builder - as in hands-on doing the creation and improvement work - or more as a developer - managing and organising others to do the work to create and improve buildings. These are very different things and require rather different skillsets. **Edit - I just saw this bit had been dealt with while I was writing ** My nephew, only 18 at the moment is exploring similar things as part of a year or two off before Uni. He's been helping me out on site for a couple of years and has now gone around his neighbourhood offering to help out. He's now fully booked by people who need extra help, but are also teaching him the ropes - this is everything from grounds maintenance, labouring for a builder, mowing lawns, fixing machinery and various bits with me including carpentry, brick work, etc. etc. He's also getting loads of practical input in how to set up and run a sustainable business. Given that there is currently a shortage of labour, I'd reckon your son could phone around some local builders and offer to help them out - possibly free - to see if it suits him. But undoubtedly he'll first be given the crap jobs to do. The problem with the college courses being offered is that the environment is totally different from the real world. I'm always accused of being too wellspoken and posh in my areas of work, including the building stuff, but what I've found is that doesn't matter for long if you're happy to get stuck in and graft. You also have to demonstrate your knowledge a bit more because some do try to get away with stuff thinking you're a naive toff! The most important thing to keep in mind is that it isn't just about building. If he's going to make it, he's also got to understand the fundamentals of running an business (probably even more important than the nuts and bolts of building). And he's going to have to understand project management. There are many great builders out there but a lot of them can't organise and/or manage a business and projects for toffee, because they're so different. Another thing that I think he needs to be aware of is that in running such a business, it's a massive grind a lot of the time, especially in construction. Very stressful and there's a lot of mental health problems in the construction industry (mostly overlooked and ignored), partly because many construction environments are really unpleasant place to work. There's not a lot of openness about this but it's better to be prepared. Beyond the self-building, my professional background is in psychology and I still work with clients going through this kind of stuff all the time (I've actually just been asked by a client if I can be a primary contact for all his employees and subcontractors for initial support). But the most important first step to assesing his capability, is whether he now shows the initiative, in part to work it out for himself and to put the time in - whether it's a course or experience, whether he likes it or not, it's going to take him a few years to learn the basics, a few years of developing skills, experience, and a network of contacts, and then a few years to get going. Patience and initiative are key and there are no shortcuts.

I think it depends on where you are and the local suppliers you've got access to and what species you're looking for. I bought my British Western Red Cedar from Cedar Direct they supply Canadian cedar too. I had good service and when my order was ready, I got a call from a yard with number telling me it was from Brecon. All very close to me. They do supply nationally.

An alternative to save money here is to sort your waste and hire skips for inert waste. Some skip companies don't do it, but many do and it's generally much cheaper that way.

That looks a bit more like it. Yes, that's counter battened. You can seal the windows with either a sealant - Soudaseal 215LM is made for window and door connections for example - or an expanding foam tape. It'll depend on the acces you have and the gap space. I would be inclined to also use an expanding foam tape between the window frame and reveal as a primary weather barrier. At the top of the window opening, ensure there is a ventilation and drainage gap for any water to drain from behind the cladding. Others on here have given some really good suggestions about ways in which you can finish the reveals around the windows. The cladding I've just installed myself actually uses reveals similar in design to yours, which I chose because I liked the look. Mind you, I do have large roof overhangs over all my openings (500mm on one side and up to 1000mm on another). Here, however, is a nice example of the suggestions made by @markc, @ProDave, and @Gone West, which is no doubt better from a weather protection perspective: HTH

Okay, in my view those details are unfortunate. Who did the detailed designs for this? The purpose of the cavity behind a facade, whether cement fibre board or cladding is a combined for both ventilation and drainage of water ingress. Normally you'd install counter battens to achieve this (if you really wanted to follow best practise, those counter battens would be machined with an angle at the top to shed water). With holes drilled in the battens you won't know if there's sufficient ventilation and it's unlikely to provide necessary drainage - I find this a bit of a bizarre way to to this as the holes will undermine the structural integrity of the battens and it must have taken ages and been a lot of work! With the windows, they should really have been fully installed to be weatherproof behind the cladding. At present you have several areas of risk, one of which is definitely the top of the windows. At the top of building openings, cladding should allow for bottom ventilation of the cavity and drainage (sometimes this is changed due to fire spread risk). There's probably little you can do now about the battens, but it's worth investigating behing the reveals and making good around the windows if that's possible.

It looks like such a typical English cladding detail. Do you have any roof overhang? From the photo it looks to me like there is just about 25mm or so for the fascia and then your guttering, but I may be mistaken? If not, then you are going to be fairly exposed. Timber cladding should always have a generous roof overhang for long term performance, but that often gets overlooked, by designers and builders alike in this country. The issue with water ingress is not just water running down the outside of your cladding and tracking back into the fabric at the reveal but also ingress to the inside of the cladding (e.g. from wind driven rain) being able to get out. Therefore, if you add some flashing, it should ideally be installed across the ventilation gap behind the cladding and tucked under the membrane. I notice from your photos that there doesn't seem to be any bottom ventilation provision at the reveal. If you're so inclined, you could remove the reveals and take a look to make sure the top of the window has been properly finished for full weather protection within the frame (behind the cladding) and then rip down the reveal board to leave a gap large enough to both provide bottom ventilation to the cladding and allow any water to drain out. I'm sincerely hoping that what looks like a bead of silicon between the window frame and reveals isn't your only layer of weather protection - I'd suggest it would have been a neater and longer lasting finish to have used an expanding foam tape between the window frame and edge of the reveal board - this would take up the natural movement you're going to get with the timber boards and would make it easy to remove the reveals in the future in case of essential maintenance.

@Adsibob in case it's any consolation, I came from a professional background. I've worked at a senior level in one of the world's largest professional services firms. I've also been responsible for project document management at one of the world's largest engineering consulancies, building everything from airports to pharmaceutical plants, oil refineries and oil platforms. I used to think I was reasonably adept at running fairly complex programmes and projects...until I decided to self build... I found that the rules we think apply to the world of work and projects don't seem to penetrate the twilight zone of construction, an industry which is by far the most dysfunctional I've ever come across. No only this, it's plagued by some weird contradictory mix of last minute, just in time, and the never never. One of my most bemusing experiences of this was when the crew turned up to install my temporary electric supply. The van turns up on time at 8am sharp. The crew come and look at the trench I've dug. Tell me it all looks fine. Then tell me they're going to have their tea and will be at it shortly. They then sit in the van for half an hour drinking tea and reading whatever red top is their flavour. Then they get changed and about an hour later kind of get to work... I won't go into the EWI ordered over a year ago last March and which is only now getting installed! Take a deep breath.....and as both @gc100 and @ToughButterCup say, it seems to be the nature of the game. * and yes, I know there are some good ones our there.

Render Carrier Board Tray - helps to provide a nice clean finish and drip edge - try here for starters: https://ewistore.co.uk/shop/render-carrier-board-tray/ HTH

This would be fine.

One way of looking at this that nobody has mentioned is to compare current situation with buying a ready built house. Round us people are struggling to find houses to buy and prices have gone through the roof. If buying a plot right now, I'd count my blessings that I've got a plot and relax in the knowledge that unless I'm massively flush with cash to speed through the whole process, things will be clearer once I've got planning and design sorted out, let alone got all the builder quotes in. But then I've done all of it myself so it's taken a rather long time, but as @nod said, it is self-build!

No, you need minimum 50mm ventilation gap below the ply supporting a metal roof. Speak to your metal roofing contractor for their recommended detail as there isn't necessarily a need to use soffit vents as you can 'hide' the ventilation behind/below certain overlaps in the roofing/fascia/soffit buildup, or alternatively use verge ventilation instead. All depends on the whole picture.

Simplest and no upfront cost way is to open the windows for a while every day. Second is to install some basic background ventilators through the wall. For example: https://rts.vents.co.uk/blog/products/background-ventilators/ https://www.bpdstore.co.uk/fresh-wall-vents/c/49?GVWS Then if you want to spend a bit more money and you think you need additional ventilation, look at powered extract. And then, as @SteamyTea suggested, look at single room MVHR if you have a need for good energy efficiency. I wonder where his mind has wondered with thoughts of excessive moisture/smell and internet disconnect. Worth serious consideration...? Some thought is required when installing ventilators to ensure they work and don't over ventilate or cause unwanted draughts. This is often the reason why a lot of people think natural ventilation doesn't work and/or is energy wasteful.

Have you considered British western red cedar? It's more knotty and has a slightly shorter life expectancy but I'd expect it to be half the price of imported cedar under normal circumstances, might be even better value right now. Depening on your location, you could try Vastern Timber or Cedar Direct for price.