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Hi All I'm looking at doing my second self build. Which will be a traditional new build. I did a listed barn conversion 18 years ago. I must hold my hands up to a bit more knowledge than that though as I worked in technical depts. in some of the national house builders for 20 years. Most knowledge is of traditional brick/block construction, plus a bit of timber frame. I have done pretty much every site abnormal known though. I have precious little practical experience in renewables, but did a little PV roofing about 15 years ago. From experience more innovation is done by the self build "crowd" than any of the national builders!

I have just found myself weeing on a limestone tile sample. It's a new low. In my defence, it was part of an extensive testing regime to see if they will work in our bathrooms, and we have a 6 year old with poor aim and a baby. Anyone got real life experience of living with honed grey limestone?

The last two weeks have been very productive! The rendering is done and the scaffold gone.The pellet stove and thermal store have been installed as far as they can be for now and the plasterboard work is coming to an end. We had to pay a visit to David L Douglas last week to finalise the kitchen- colour, door styles, worktop, handles, sink etc they are very thorough in getting it just right. The plasterer will be in tomorrow and my kitchen and utility floor tiles arrived yesterday. After my previous meltdown things seem to be on the level again, for now! The budget has had to have a few tweaks but nothing too major. A visit from SP energy networks project manager last week revealed the power won’t be with us until October 22nd( they’ll start the digging then but he has assured me we will have power by the end of that week) bit disappointed in that but on the other hand we should be finished and ready to move in by then. So this weekend we will be digging drains to cope with the run off from the field up the hill from us and getting the house drains in, definitely onwards and upwreards

Now we're cooking. Subfloor poured today, so one row of quinnlites on their edge and we're at FFL. Provisionally looking at 3rd wek of October for the kit to arrive, scaffolder is booked on standby today, it's all moving on now.

Our asbestos removal was zero rated.

How on earth can stating the standard way that mixers have been used for donkey's years be condescending to anyone? I'm sorry, but I'm not likely to thank you for making the potentially dangerous suggestion that anyone should "use muscle power to help the first 10 degrees of rotation". To even think that was a reasonable thing to do shows a disregard for the obvious risks. The key here is the way in which information is conveyed, and whether or not a new member of this forum, with little or no knowledge, might assume from the author's writing style that he or she is knowledgeable and so their content should be trusted as being accurate and safe. I'm afraid many of your posts do come across as if you have become an overnight expert in several areas, when just a short time ago, in May of this year, you appeared to be disparaging about those of us here with years, or decades, of experience and admitted that you knew little about trades, when you wrote this: Apart from the above being factually incorrect, in that I cannot find a single reference anywhere in any of the content on this forum that states, or even implies, that "Early encounters with the good denizens of the BuildHub forum tarred me as a hopelessly naive computer programmer fit for little more than making tea onsite". All I can see are people offering free help and advice, coupled with responses from you which seem a touch arrogant and supercilious. This is a generally very friendly place, and a lot of that relies on give and take, plus members having a bit of humility when they make an error and correct it. It's not acceptable, in my view, to express arrogance, as in "These points are now clearly stated in the public domain because of my follow ups. You should be thanking me.", especially when the aspect in question, never hand assisting a powered mixer, has been in the public domain as plain safety common sense since I was a small boy. I've made enough errors here, and tried to correct them whenever I've found them or they have been pointed out to me, to have learned that it's generally more acceptable when trying to make a point to be slightly less assertive that I would be inclined to be normally. We all have to accept that there will always be members that hold contrary views to our own, and they are entitled to do so. The problem arises when contrary views are stated assertively and promote an activity that has long been known to be dangerous, and has caused a number of serious injuries on building sites over the years. As a forum, we should collectively try to make sure that we don't promote anything in an authoritative-sounding post that is potentially unsafe or unlawful.

I see nothing condescending in that at all plain simple instructions i have taught many a 16 year old lad to use a mixer if they turned it off loaded they would get yelled at there is no need to turn it off loaded. Follow my. Instructions like a good lad and you will be fine. Now thats condescending.

Hi The old fashioned way works ok too!. This video shows setting out in plan form only, but it shows how to set the profiles too. https://www.youtube.com/watch?v=7dN3Iku0Bns If you set the string to a known level. Say 500mm above DPC. then work out the distance from this level to the required bottom of foundation. Make a stick this long - this is your "traveller" the digger driver then uses the stick at each point along the string for his depth. Similar to this method for digging a trench:- http://www.ruralworks.com/reports/profileboard/ProfileBoard.html Costs are some bits of wood, and a ball of string. This method would be used for most buildings before laser levels were invented.

@JSHarris summarises things nicely above but it should also be pointed out that the amount of energy available in the wind varies tremendously with the wind speed. It's that energy which the Betz law says what proportion you can extract. The available energy is proportional to the cube of the wind speed so wind at 6 m/s has 8 times as much energy as at 3 m/s. An increase from 6 to 8 m/s doesn't sound a lot but it more than doubles the amount of energy available. Or, to put it another way, the decrease in wind speeds caused by buildings and so on really stuffs turbines even if they're cleverly designed to deal with the turbulence. Maybe one day somebody will design something which is actually useful for this sort of thing but it's really not worth wasting much time on until they (or, better, somebody else) produces good figures for actual power production. The reason it's cubed is kinetic energy is proportional to the square of the speed and the amount of air you get through the turbine disk is proportional to speed as well.

I like Egger Protect 22mm chipboard. The coating is permanent and on both sides so if you have subsequent leaks it should not turn to Weetabix too quickly.

We had 22mm CaberDek laid on our first floor while the frame was being constructed. It comes covered in plastic and the joins on ours were taped as well. It survived out in the open.

How about an in-wall 200mm vent between the snug and the hall? You can get "silent" fans (e.g. ~25-30dB) which can shift maybe 2m³/min which will be enough to stop the room overheating.

There's your problem right there. You should have attached them with a suitable adhesive!

@pdf27, Assuming that you have a conventional "double-back" layout for your zones and also have access to the Ansys heat flow modelling, then you can easily set up the heat flow model that I did, which is to approximate the slab as a concrete tube the length of a zone run and the radius set by the slab thickness and pipe spacing. This radial symmetry makes give a 2 spacial and one time dimension model which is computationally solvable over 10s of hours. OK, the radial symmetry assumption breaks down in reality because the UFH pipes are not in a cylindrical medium but set in a slab concrete with a insulating surface below and a radiant one above. Even so the model still gave an excellent prediction of the time response of the slab and the heat-off impulse response in the both the model and the actual slab shows that the radial component dominates the heat flow during heating: it's an extremely useful model. To me what this all underlines is that the slab itself is the biggest heat capacitor in the system, so there is little point in adding complexity of external smoothing using TMVs and buffer tanks. So long as you are pumping enough heat per day into your slab then a passive class house with warm slab + UFH + cellulosic filler will stay comfortable. In my experience your divide the year into three broad zones: No active heat management is required (roughly 6 months / year) because the intrinsic heat excess is enough to keep the house at a comfortable equilibrium and MVHR exchange / bypass gives adequate trim. One per day heat adjustment is sufficient (roughly 3-4 months / year). This is my overnight top-up / cool-down. Again so long as this adjustment gives enough bulk heat-balance, the MVHR exchange / bypass gives adequate trim. One per day heat adjustment is insufficient (roughly 2-3 months / year). Here for the mid winter months a single heating period starts to give a daily heat ripple that is noticeable, so you need multiple heating periods per day. For the UK climate range IMO you will never need more than 3, but at 4 the ripple will be less than 0.1°C. At the moment I use the day-to-day average temperature as a control feedback to compute the total amount of daily heat (and in future cooling) needed to apply. Because I use a fixed input heater this maps directly to heating time. If you are on E7 it does make sense to have an asymmetric cycle with a bulk heat overnight, but the tops can be spread through the day. It sounds like you are going to adopt similar ASHP heating scheme to the one that I plan to and @jack has done, which is to set the ASHP output temperature at a low setpoint (in my case around 27-28 °C). You then need to control the mark/space ratio to maintain the overall daily thermal balance. And the CoP at this set point is excellent. (Though if you have kids and use lots of HW and want to use your ASHP to preheat this then this would greatly complicate this approach.) There are a number of strategies here, eg. use a fixed cycle (say 6 hours) and then control the on time or use a fixed on-time and control the off-time to give a variable cycle, but IMO these are all based on macro thermal balance. This will work well for my house, but if you have "acres of S facing glass" then day-to-day highly variable solar gain will become an issue that you need to factor in. Jeremy and I started out at very different design conclusions from a very similar problem analysis and our solutions are conditioned by historic investment decisions. Even so we have significantly converged in our approaches. Jeremy uses a single internal datum, I daily average a couple of DS18B20s measuring room temperature. To be honest, if mid-winter heating was my only concern then I'd stick with the largely E7 Willis approach. Yes, the running cost is maybe £300 p.a. more than using an ASHP, but I have no complex mechanical systems to maintain and to replace every 10 years or so, so there is no cost benefit case here. The real issue that makes me plan to introduce an ASHP is the summer cooling one: for about a month a year, I need to dump heat from the house actively to keep a comfortable internal environment, and I can't do this by an additive heat solution. One last comment. I've mention the impact of solar gain which can throw a "big spanner in the works". You can get very sunny days in December and if you have a large south-facing area of glass, this can be a big pulse of kWh into the house. The other one that causes us fun is visitors. When our kids+family or others come to visit, then just the heat and activities around hosting these guests adds environmental control challenges. For example, 6 people sitting in a room will cause it to start to warm up noticeably!

Nothing you wrote was in anyway condescending, @Russell griffiths. The problem is really with people who have little or no experience of working day in, day out, with mixers advocating something that's out of the normal safe way the vast majority use them. I was shown how to use a mixer by a builder, when I was about 13 or 14. It was a petrol mixer, and I can remember him giving me the same instructions about always starting it empty, and that was over 50 years ago. Not leaving a mix in a stationary mixer, but tipping it into a barrow was also normal practice, even back then. This has nothing to do with generators, either, it's just the standard, safe, way to use a mixer, always has been and always will be (until someone invents something else to mix mortar and concrete).

Looking at the glue lines is a good way to check if you will have any issues - if they are swelled up and foamed properly then there won’t be a problem as the glue will have sealed all the edges. A sharp floor scraper will clear them off when they are properly cured. The problem usually occurs when they aren’t sealed on cut edges around openings and similar - brushing on some glue will help.

The flat rate vat scheme is available to ‘low cost traders’ and as the name suggests they pay HMRC at a fixed rate. This is supposed to make it much more straightforward to work out how much VAT is owed. The problem for traders operating under the scheme is that if they zero rate a job they still have to pay HMRC the flat rate, so not many traders using the scheme will want to work on zero rated jobs. https://www.crunch.co.uk/knowledge/tax/flat-rate-vat-scheme-limited-cost-trader-test/ https://www.gov.uk/vat-flat-rate-scheme

The timber frame will be substantially built by the middle of next week and I'm thinking through and organising the next stages, so this post is to help crystallise my thoughts and offer them out for anything I have missed that is time-critical. MBC will be working over the weekend and the build will be substantially finished around Tuesday or Wednesday. They are going to leave out a few of the stud walls, the ones that form the walls of the landing, until they return to do the air test, simply because it makes moving around up there much easier. Once the air test is done, they'll put the stud walls in place and blow in the cellulose. I've got a couple of site visits from roofers over the next few days; it's crucial that I get the eaves courses done before the PV installation as it can't happen without them and they are really tight on time slots at the moment. The PV is due on the 26th/27th September, immediately after the glazing which goes in on the 24th/25th. Now that I have a house-shaped object, I have requested a site visit from the glazing installation manager to make sure that I'm clear on everything they need to do their thing. He's coming out next week, so that gives me time to get any alterations to the scaffolding scheduled, as it will be impossible to get them out on the day if there are any problems and I'll miss my installation time slot, which will put everything else back. Running in parallel with this is the garage flat roof and quite a few fiddly bits on the build that need tending to as soon as possible. The garage roof needs its GRP on because it won't be watertight until this happens. Also, there is a flat roof section over the stairwell, next to the main pitched section and it would be good to get this done whilst all the scaffolding is up to that height. Other flat roof sections are the balconies, and then the gutter runs behind the parapets will need lining with GRP or something similar, but I need to look more closely at that. On the subject of balconies, I need to get my balustrades sorted. I haven't started getting quotes yet or even gone beyond sourcing a couple of suppliers. I don't know what the lead times are for these things, but I'm working on them being more than a couple of weeks. Likewise, I need to get quite a bit of aluminium fabrication done for the EPS upstand and to cap the parapets at the top of the ground floor, pretty much all the way around. If anyone has any suggestions for anything other than aluminium, I'm all ears! I currently think that aluminium is a good option as it can be powder coated to the same RAL colour as my window frames and should all blend in nicely, as well as being formed to the exact measurements needed. At some point, I need to get my guttering and downpipes sourced and attached, but the downpipes won't go into final positions until the cladding is on. Again, running in parallel to this lot, I'm thinking about when it's best to get my groundworker back in to dig out the drainage runs, amongst other things. I'm thinking some time around the first weeks of October, mainly because I have to get a trench dug for the service alteration and burial of the electricity cable, which has been booked for 17th October. Other things that need to be dug out for are the sewage treatment plant, the land drain for the output of the plant, the rainwater storage tank, the trenches for the rainwater run-off into the tank, trenches for a brine loop in the field and finally a socking great pond in the field that may then fill up over the winter. I daresay that this isn't a comprehensive list of holes to be dug, but it will do for that couple of weeks. Moving to things to do inside, most of it will happen after the air tightness test, which will happen after the glazing and all doors are in, but also after the inlet and outlet for the MVHR have been put through the roof and sealed. This will also need to be done before the bulk of the roof is tiled. After the air test has been completed, MBC will then blow the cellulose into the frame and re-seal the holes they put in to add the cellulose, and then first fix can start in earnest. I've made a bit of a stab at the lighting, switches and sockets plan but I'm still pondering a few things on that (like, I don't know half of what's out there and what I might like) so I need to get my act together in order to be ready for first fix. So, all of that lot should see me through to the first fix work which is in hand and I can go on to contemplate the joys of sanitaryware and generally making the place look like a habitable house rather than a house-shaped object. One thing is certain - it's going to be a very, very busy time from the end of September onwards so the more I can get planned out now, the better.

Does a lady going through *the change* not produce X10 the heat of a typical person. Might be an important control matrix consideration, especially if her sister visits too

Some things to add to your to-do list: 1) All the penetrations (MVHR, electrical, CCTV, gas, water, whatever etc) through the external walls BEFORE they blow in the cellulose. It's a difficult thing to do afterwards.... It means you will have to start planning external lighting, external power, CCTV, satellite dishes, aerials etc. 2) Fascias and soffitts (not sure of your roof construction) whilst all the scaffolding is in place 3) Make provisions to control the rainwater off the roof, at the earliest opportunity. Fit gutters and temporary downpipes. Get the water into rain water system, if installed but at least get it away from the house. 4) Noggins on external framework for everything that needs to be attached - satellite dishes, aerials, balcony fixings, etc, etc 5) When is your scaffolding coming down? Can you complete the groundnworks for drains, rainwater connections etc whilst the scaffolding is still in place? You're doing well, keep going....

Welcome to BuildHub, great to have you aboard.

+1 to welcoming you to the forum. Really good to get someone new to the forum who is not only willing to contribute but has the depth of knowledge you have. Hold on tight though it can be a bit choppy out there !! ?

I wish I could offer some advice but I'm still in 'sponge' mode and just soaking up your output so I can only offer encouragement. From what you say it looks like you've got pretty much everything covered but I suspect wise wo/men will be along soon to highlight any omissions in your planning. Good luck with it all.

Welcome @Tyke2! With your knowledge, I look forward to learning from your questions and answers.

Just a quick heads-up for anyone like me who has never given much thought to these. I decided I really needed some for my build now that the first floor is going up, and it turns out that the window company insist on them for installation. I opened a trade account at my local Howdens Joinery this morning and tomorrow, I will be the proud owner of a set of temporary stairs for the princely sum of £119 + VAT and £20 for delivery. They come as a standard size which isn't quite tall enough for my build, but the MBC team will do the necessary and make it fit.

Nothing wrong with that. It’s what they are sold as anyway.

Thats actually Egger Protect - I have an account with MKM. Good stuff and really decent service from the local branch too.

Those would have suited me rather than the ladder that I only plucked up enough courage to go up once! Didn’t think of it TBH. I’m glad there is no video of me going up and down the ladder that day. It wasn’t pretty TBH ??

Snap - MBC's handiwork: Got slightly wobbly after several months, but added a couple of battens and some screws and it did us until the build was finished.

Very true @Ed Davies. Sometimes trying to simplify stuff as an attempt at clarity leads to technical inaccuracy, and I didn't want to get bogged down in the "power is proportional to the square of velocity and energy is proportional to the cube of velocity" stuff, for fear of the post being too long and too technical for some!

Oh yeah . If you meet planners again * always * discreetly record the conversation. Good way to make knives ....

Planning is a pile of shit . Half ‘plans’ , half politics . We experience about 5 refused ; lost 3 appeals . But I never gave up . I’m not familiar with your exact application but you might want to try the ‘wratchet’ Approach . Just get ‘bits’ passed as you go - then hit them with it . Admittedly this takes time ( years ) and costs a bit . Trust your own judgement....

What a load of bollocks, this place has given me no end of good advise, advise that would have cost me dear (if I could trust the source). I and others here are benefitting from genuine knowledge from either professionals or people that have discovered (many through ill fortune) how things are done or how they could go wrong. Frankly I have never met such a genuine bunch of helpful people. Although I have only met two of the members I almost feel like MOST are my friends.

Is it? Really? Off the top of my head I can think of quite a few hands-on self-builders (excluding myself) that are regular contributors on here. Ones that stand out as having made a tremendous effort on their own, with little or no local help, are builds like @Crofters, on Skye, the brilliant build in the Carbeth community by @Tennentslager, the lodge built by @iSelfBuild, the lovely home that @Declan52 has built for an astonishingly low budget, with his own hands from the ground up, the trials and tribulations that led to @ProDave getting a digger and doing most of the build of his home himself, much the same with @recoveringacademic, who, like me and you, started with near-zero practical knowledge of the construction industry, as well as many more that you could find if you looked around. Sure there are some with construction industry experience self building here too, and doing a lot of the work themselves, people like @joe90 and @Russell griffiths spring to mind, but there are others. Have a good read through the trials and tribulations of some of the builds on here, and read the responses from others to those trials and tribulations, then see if that still, on balance, matches your assertion that we, as a large group of self-builders and renovators are generally "quite hostile to the genuine aspiring hands-on self builder". My own view is that we are, collectively, quite the opposite, and if anything we probably tend to overwhelm some aspiring self-builders with well-intentioned advice initially. The key to how things go from there is how individuals respond to that advice. Those that take what they need from it, and get on and do a bit then thank people and come back for a bit more advice are very much welcomed.

Accepted - and that causes an unfortunate confusion with the regulated term "Competent Person" used for somebody qualified to do specified tasks in each trade. I think this is not quite the fully nuanced picture for rentals. And the whole thing is a festival of grey areas and weasel words. The legal reqiuirement for electricals in a rental, which I think is the underlying standard everywhere in the UK except possibly Wales where I have not checked, is that they are required to be safe and fit for purpose (or words to that effect), so in an enforcement situation there is professional judgement involved and sometimes the Council assessment staff may not be competent persons, never mind Competent Persons. The status of an EIC for a rental is that it is regarded as "best practice" to have one every 5 years, and would have significant weight when such a judgement were made. In practice it is all so complicated that it is far easier to invest in one rather than mud-wrestle the bureaucrat-monster, even if your properties are electrically safe. If a decision goes against you the consequences are draconian, and can be enforced eg in England as civil fines up to £30k by the Council on its own, which are very difficult to challenge. However (for completeness) an EIC every 5 years is mandatory in law for certain larger Houses in Multiple Occupation. In England they will be mandatory for Private Rentals before long anyway. I support that for EICs, though you can get me to be very rude indeed about some of the garbage being imposed via Goldplated LL Licensing schemes. But an EIC every 5 years is also identified as an (alleged) 'mandatory' requirement in many regulatory situations. One such is the Scottish Government Repairing Standard for Rental Property - link to electrical provisions, and enforcement can be via the First Tier Tribunal for the "duty to carry out Electrical Safety Inspections". Duty of care is a nebulous Common Law ( I think) concept. That is a bugger to disprove without an EIC, and he SG are trying to pretend that the EIC is in fact mandatory. In England, every Landlord Licensing Scheme that I have seen has such a provision, along the lines of say Nottingham's Selective Scheme for example. This is a set of words designed to impose a requirement that goes beyond the law.

Previously I believed I had helped in preventing you removing part of your foot with the angle grinder by showing the correct way in using that, just like posting on how not to burn out the belt on your mixer I believed it was of help to you. If for one minute you think I post a reply for my own gain by belittling you then you must be a bit confused. any knowledge i share in an answer has been gained by doing that job many times, earning my living from doing that job, not googling the answer, guessing or asking down the pub, I only deal in cold hard facts of what I know. You came on with a question about mixers and generators of course you can stop your mixer with a load in it, and start it with a bit of help by pushing it around, why not. Because its WRONG WHY DO IT, there is no need it’s about as wrong as laying bricks FROG DOWN, putting muck on a dry spot board winging your perp joints they’re all wrong, but still get done daily by people with a lesser grasp of common sense.

I would agree with Jack, let them have access to get a check done if they wish (and if required, agree to deduct the cost of replacing the CU off the sale price). Would a check throw up the issue of the bathroom cupboard socket issue previously discussed?

Indeed. I prostrate myself before the feet of the world's greatest living comedian self-builder. I only wish that I'd been able to accumulate the knowledge and wisdom of self-building you've acquired over the last few weeks, over the course of the 6 builds I've done.

Jeremy, I don't follow why you're willing to prepare an EICR and/or pay money to upgrade a CU on a house you're selling. If I were a potential buyer who didn't know you, I'd consider this behaviour concerning, as it definitely isn't what civvies do in this scenario. At best it looks like you're desperate to sell, which might encourage a late, lower offer. Offering to prepare your own EICR, in particular, is something I'd counsel against. Again, to someone who doesn't know you, I think this would look highly suspicious, plus I don't think you want to be the one in court arguing about your competent person status in the (admittedly highly unlikely) event something goes wrong. If they want an EICR, why not just tell them that you're happy to give someone access to prepare one? That's what people without your background (ie, most of us) would do. If they're committed to buying and this is just a formality, offer to allow them to upgrade the CU at the same time to reduce costs. To me, that sounds like the behaviour of someone confident that there're no problems with the wiring (and perhaps you can then give them your background and explain to them why you know it'll all pass except for the CU). Just my thoughts - I appreciate that others will have a different view.

As above, stick with it, get the appeal in, yes a consultant might be good as they tend to understand the complicated policies (mumbo jumbo language) better than us lay people. I found the appeal office very helpful. (And we won hands down ?).

@oldkettle Stick with it and don't give up. You can beat the buggers.

This thread highlights the very worst of selling houses, surveyors and solicitors. In this case the wiring is in good order, wired to an compliant with the standards in force at the time and time still just as safe. In the real world it would now benefit from an upgrade to a new consumer unit to give the better protection of rcd's and mcb's But surveyors like to get their teeth into this sort of stuff and make a mountain out of a mole hill and scare the poor buyer into thinking the house is about to burn down and needs an immediate full rewire. And sadly most buyers just believe the tosh they dish out. @JSHarris since you know a local chap, can you not give him your test results and pay him to issue an EICR in his name with those findings?

Wiring regs just say you have to be competent. So no reason at all why not. But if the purchaser notices your address is the same as the address of the property being tested they might raise a concern. In my case it is handy having 2 addresses, e.g when I do an EICR on the old house, I use the new address. When I do an EIC for the new house, I use the old address. So just use your new address and there should be no problem.

Thanks for the replies :) It's an old brick barn and the alterations it has had, roof failing and general movement over time have taken its toll. I've underpinned the entire building and extended the concrete inside to serve the new inner leaf. (My username is based on this joyful task) The leafs will be tied together with wall ties resin bonded into the existing brickwork. Insulation will be full fill. The worst measurement i have shows that one wall is > 100mm out of true at one end due to the wall bowing and twisting at the same time. Most are +/- 50mm at some point along them. If I changed to timber frame now I'd have to submit changes to the plans and whatnot. It's an option i suppose but i'd prefer the new inner leaf.

So watching the lorry negotiate the corner from lane to driveway last week made me pause. Then a chat with our nice new neighbour, and following that an hour's work tonight. Result? a few quid for posts and much more room to turn. Excellent.

Buy a petrol mixer instead and use the genny for light stuff as having one running 8 hours a day is horrific ... it will make you want to bury it in concrete.

Your valid argument is that you have dug to a depth of 500mm+ at 4/5 different locations across the site and found sandstone at this depth. Unless you are going to attack this with either a 20t plus digger or a fairly powerful drilling rig you won't get anywhere near 4m. Maybe she would be happy sending samples of the sandstone away to be tested. Either get the spade out or get the groundwork guy to go at it with a digger. Either way will be much cheaper.