Paul K

I know it’s kind of a ‘how long is a piece of string’ question, but can anyone give me an indication (or point me to a source) of comparative weights of different construction methods? SE has given me some worst-case foundation loadings using ‘traditional’ brick & block, but I just wanted to compare the kg/m2 for SIPs, timber frame, Porotherm, Isotex, etc Thanks in advance.

We’re looking to build in a disused quarry but because there’s a lot of overburden, we’re having to drill boreholes to establish exactly what’s underground so that the SE can come up with a plan for the foundations. We're still some way from having a specification and I know there are a lot of variables, but I fear that it's going to need deep piles. My question is simply one of budgeting – is there a rule of thumb for getting an indicative cost of concrete piles? Cost per metre maybe? If anyone has any experience of this, or can offer some guidance on piling costs, your thoughts would be appreciated, even if it just gets me some ballpark figures.

Thanks all. I'll give estimators.com a go and see what they can come up with.

We are in need of some initial ‘ballpark’ estimates of build costs for our project - can anyone recommend a quantity surveyor in the Derbyshire area, preferably one with Passivhaus experience? Any suggestions would be appreciated.

Latest update from Kent: We paid £500 + vat (!) for a consultant to report on the nutrient load for our development. It turns out that our 4 x self-build plots will need to offset a total loading of 3.23kg of nitrates pa (zero phosphates), irrespective of what the final designs/specifications will be (we’re only looking for outline consent). Apparently 1ha (10,000m2) wetland can deal with 900kg of nitrates (on average), so 0.09kg needs 1m2, which means we need to get hold of 35.89m2 of wetland to cope with our 3.23kg. Given that a wetland needs to be at least 2.2ha in order to function properly, I’ve approached a couple of developments with their own wetlands to see whether they’d sell us a 6m x 6m slice, but with no joy. The general reason is that they don’t want to add any further complications to their mitigation calculations and risk jeopardising their approval, but they also want to hold on to any spare wetland capacity to offset other projects. Interestingly, I’ve been told that the local council are struggling to find any land suitable for converting into wetlands, and when they have found any, they’ve been outbid by private developers. So it looks like they’re not going to be able to offer a mitigation credit/offsite contribution system anytime soon. And so it drags on.

I'm hoping this message reaches you in time, and would be interested to hear how your DRP meeting goes. We'll be undergoing the same ordeal in mid-June, although we will be armed with a planning consultant, architect, landscape architect, ecologist, etc, etc. I'm mightily impressed if you're tackling this yourself! We are meeting on site and then travelling to a meeting room arranged by the DRP (as part of their fee). They are allowing 3.5 hours for the whole process. If it helps, this is an extract from one of their emails: Presentation Guidelines In terms of the format of the presentation for Design Review. The list below provides a guideline on the information that could be provided which will depend on the stage of the scheme, the site analysis however is essential: · Location plans – 1:1250 · Existing site plan – setting out existing buildings, land ownership, listed buildings, conservation areas, pedestrian and vehicle movement etc. and urban design analysis if undertaken · Proposed site plan – setting out landscaping, car parking, pedestrian and vehicle movement etc. · Aerial photographs, if available · Proposed plans, sections and elevations · 3D images of proposed scheme – photomontages and views · Proposed site sections and elevations to show relation to context · Views in and out of the site, showing the project in context · Indicative details to illustrate the proposed architecture. A few other points I've picked up in the process might be of interest: If you give the manager of the DRP a heads up on what the project is beforehand, they can select panel members with relevant expertise. And some DRPs specialise in certain types of architecture - no doubt you've selected one that will know about sustainable buildings. It is important to get an understanding of what your DRP will expect to see - our architects have done a number of these presentations and all panels seem to vary in their expectations - some will want just a basic concept so they can suggest design ideas, while others will want to see more detailed plans that they can tweak. Our architect has already had an email checking that 'you haven't done too much have you?' Is your planning officer attending? Apparently having him hear directly from the panel can streamline things later on as he can understand how you've taken the DRP's suggestions on board. Our planning officer suggested a DRP that he had dealt with before, but para 80 applications don't come across their desks very often so they have to get help. However, they are usually interested and keen to be involved - handling such a scheme looks good on their CV after all. Have you budgeted for a second DRP? If they feel your design doesn't meet the para 80 requirements, you will probably need to go back with a revised presentation to get their support. One final point for your presentation, you need to show that your para 80 project specifically relates to your site - the phrase quoted to me is that the house must 'fit here and nowhere else'. And one final worry - whilst DRP support does usually result in planning consent, apparently less than half of all para 80 houses ever get built, mostly because of the final cost, but often because the DRP's input results in a design that the applicant doesn't really want! But hey, we do it for the challenge. Good Luck.

Causing us a problem in East Kent. All the councils in the Stour Valley catchment area seem to have been caught out by NE’s change to the acceptable levels of phosphates (generally from farm fertilizers) & nitrates (from sewage) in the watercourse and are scrambling to come up with a policy to address the issue. The current plan seems to be for the council to convert some of their land to wetlands and then create some sort of offset credit system, but until they do, everybody’s applications are on hold, unless you can show ‘nitrate neutrality’. Of course, a system to purchase offsite credits also raises the questions of how much they will cost, how many will be available and how they will be allocated, and I fear that the self-builder will end up at the bottom of the pecking order. At the moment it seems the only way to achieve consent is to incorporate a wetlands area, which needs to be at least 2 hectares in size to be effective (so not much help for most sites) or to take agricultural land out of production in order to offset the nitrates of your development (hence larger developers buying up & ‘closing down’ arable farmland). The council also tell us that on-site treatment plants don’t help as the outflow always eventually reaches the water course. The nett result for me is that the outline application for 4 x self-build plots that I submitted in March last year remains on hold, with no resolution in sight. What I also can’t work out is how I can be expected to produce nitrate calculations on an outline application where no house plans are specified, and why they can’t provide outline consent with the nitrate issue left as a reserved matter, based on the final design of the houses. And, of course, no one is addressing the elephant in the room which is the Southern Water Authority preferring to pay £90m fines for polluting the rivers rather than spend money upgrading their sewage treatment plants! If anyone has any suggestions on how to best deal with this problem, I‘d be glad to hear your ideas.

Thanks - I had pretty much come to the same conclusion.

I recently come across the Gablok system (gablok.com/en) online and wonder if anyone has used this product and what you think of it. I only ask because I tried to get some information by contacting their UK office, but haven’t been able to get through on the phone and have had no responses to either emails or voicemails. Can anybody shed any light on whether this company is still operating? Thanks, Paul

Update: I contacted selfbuild.uk.com whose insurance product seemed attractive, but they needed details of the build method in order to quote for public liability cover on the land (!!) and then informed me that their underwriters wouldn’t quote for ICF or SIPS as they were considered too high risk (!!!). Apparently they’ve had too many claims involving these two, but couldn’t divulge what the claims were for. What I’m now worried about is that ICF (my preferred choice) may have some inherent problem that carries a risk and makes it uninsurable; any comments?

Thanks. I did call Protec, but although they seemed keen to help once work was underway, they couldn't offer any 'land liability' insurance to cover us while the site remains just bare ground.

I'm about to complete on the purchase of some land and wonder if anybody can advise me where best to look for a public liability insurance product that can later have site insurance added to it. Also, as a newbie to this, are there any potential pitfalls that I need to watch out for when arranging this sort of insurance cover? Any help with this (my first post) would be appreciated.