Gus Potter

Hi Mike. Hard to tell without some wider context. Some panoramic photos required, also external ones so we can see the ground levels. It may be something as simple as the plasterer has really soaked the wall first and that has "reactivated" the latent salts in the wall?

This is what lots of people say.. until they do need to make a claim. As someone who inspects on behalf of Clients (and reports to warranty providers) who find they need to make a claim against the warranty providers. I can tell you this is a mine field and there are few friends in the desert. The rebuild cost can often be above the build cost as for example you may have to demolish, clear the site first.. which can be costly. I've not seen this advice before as it suggests a limit to the cover, maybe I've read this wrong and there is more to it? The basic shell may only comprise 20% of the build cost at times. I would ask your broker to seek two alternate quotes and provide you with the terms and conditions on when you and cannot make a claim. Read these carefully before making your decision. It's going to take a bit of time.. but I can assure you, based on my day job, it's at the very least going to inform you, it may save your skin later if your circumstances change.

@Square Feet "This is the jump I have taken since my previous blog posts (which have in themselves also been an act of ‘starting the conversation’). " This is progress! I enjoyed our telephone conversation. I have lots of different types of Clients. Some are just starting out and have little experience and you need to adjust to give the best advice that puts them on a sound footing at the start of their journey. Some Clients such as yourself have a wealth of experience and technical knowledge. Here we can skip some steps and more quickly go into technical detail, for example what detailed risk the site may pose all the way up to how you are actually going to build it on site. The conversation can quickly move to a position where can test our ideas against each others knowledge and experience in a free, open and enjoyable manner. That is why conversations take time and are invaluable in all cases. At the end of the day building a house should be fun and rewarding. It should be fun for the Client and for me also as the designer. This is achievable if you plan well, get good advice from folk where you may have weak spots in your experience. If that advice is well presented and informs you then it allows you to make evidenced / risk based decisions. The best news is that the seller has made contact and you have met in person. I’d be gutted if I saw the plot reduced to what I would have paid at some point in the future when I had already committed to a compromise plot I don’t like as much. He was generous enough to not reject it right away but instead to say that he would think about it and talk it over with his partner before getting back to me sometime next week. I can ask no more than that. At this stage there is everything to play for. The key here as you know is to keep the negotiation channel open. You want to buy, the seller sell. I think there is reference to this concept in Adam Smith, 1776: The wealth of nations. Rooting for you!

Good post. First thing is the location, It's windy up our way and often, thus local knowledge prevails. It's so windy that cold roofs if not too big work fine. But if you want to now heavily insulate and make air tight then you have a big problem. What you are missing is that you are trying to apply modern regs to an old structure. It's very hard to achieve, and expensive. Have you considered targeting easier areas to improve the thermal performance?

How does this happen?

I do like your idea of foam glass. I've designed using this and in the right application it's fantastic stuff. How ever.. I'm very sceptical about how folk get different work packages and don't coordinate the design. You have to get your head around this. KORE etc are not here to do complex details for you or take on extra design liability, they are there to sell their product. Here is a thing I would want to understand more about. You show the soil under the existing stone wall at an angle of about 45 degrees. If that is clay then it is going to dry out and shrink like fury. If it's gravel then you will disturb it, it may fail suddenly during the build. Also you are reducing the "confining, call that a confining pressure" load above the level of the foundation by introducing lighter weight material. In other words, the soil around the found is to some extent stopped from squeezing upwards by the soil at the moment. But now you are reducing that load. The best advice I can give you is to take on board the concept but think about how the ground is going to behave, builders being rough and so on. There are far too many idealist thermal details on BH and few that understand the soil and how you build off that. You should discuss this with your SE, even if you have to pay them a bit more.

Indeed. There is a huge learning curve to go though, but if you persevere it's worth it at the end of the day. This is also true! Basements carry higher risk.

What you are doing is on the face of remarkably tricky! Your builder is showing positive signs by asking about this. Yes you need different types of cavity closing and the cavity ventilation details change depending on location for example; above the windows, up the sides and under the cills! It takes a lot of experience to get this these details correct and coordinated with say MBC. Unfortunately I can't read the detail as it seems to be a screen shot. The fundamental "hard thing to do" is to have a ventilated cavity, that get's closed if there is a fire. I and others may be able to help. I might even post some of my drawings that show examples / give you pointers on the key things you need to consider. But first I would want to see what and where you have got to in the detailing stage. Can you post the actual drawings you have rather than screenshots?

You make a good point about the skills you have, I accept that. The regs have become a lot more stringent particularly in relation to portal frames on or near boundaries. Best thing you can do is to give your SE a call and discuss.

Thanks for expanding on my good news story! I hope Rawlins Paints don't mind me singing their praises but attached is their painting instructions, that mentions how much you can thin the paint. They also supply the wet film gauges so you can measure your paint thickness. This is power to your elbow if self building. Yes.. heavy steel sections can be designed where they don't need fire protection. In a fire we are allowed to reduce the imposed (live loading) as the chances of the building being fully loaded up and a fire happening are smaller. Us SE's design on the probability of all load acting at the same time. If we designed for the worst case of everything happening at once then that would be.. not practicable / justifiable on a risk basis. Yes, I also have no doubt many buildings are under-protected. Build hub Rawlins Thermocoat WI, WO & S APPLICATION GUIDANCE (5) - Copy.pdf

I was generalising. I makes no difference as you should know. The condensate seal trap works the same way. It does not matter if it is internal or external to the boiler. The fact is that if water backs up in the rain water pipe it's going to piss out inside the house big time and wet all the electrics for example. . Of course it triggers a cut out of the boiler but where does the over pressure from the rain water pipe go then. If the rain water pipe backs up then the pressure head is at gutter level say that is 2.5 to 3.0m head. In the round the thing stinks. This sounds like a bit of a straw man argument. Are you serious? A Pressure relief valve into a condensate pipe? Can you explain in lay terms?

Hiya. To provide a bit of context, much of my initial SE training and Masters research was on portal frames. I know enough to make a contribution on this type of design. Here is my offer. You can call me on the phone on (mobile number removed, PM for contact details) for a 15 -30 min chat. It's free for BH folks! This forms part of my pro bono work that is good for my soul, my primary qualification is in Civil Engineering, you work for the public. Text me first so I know it's you. I'm pretty deaf so sometimes miss calls. I use my own name and can be easily found on the internet.. I get some interesting calls and offers, these range from "massages" to lots of "financial" offers and other "stuff" that actually breaks up my day, hence me filtering calls. The section sizes you quote might be dependent on your eaves height, wind loading and the types of finishes. That the best I can do for now.

Ok @Nickfromwales and Karen. To expand, my mum is 95. The following happend to my neighbour. The rainwater down pipe got blocked and the water backed up. The water then flooded back up the discharge pipe, over flowed the tundish inside, soaked the electrical fuse box, soaked the floors. Karen. You are right on this. If you need some help then happy to chip in with a draft text to support a complaint as I'm sure @Nickfromwales will also do.

I agree how on earth can this be justified. Now they might say well ok we are following the gas regs we have the right tun dish inside so the over pressure is discharged. Putting my SE hat on I'll say if that pipe freezes you can't have water pouring into the structure. Now the building regs support my statement. It's a disgrace. Between you and I @Nickfromwaleswe could make hay with this compliant! And to do this to a person of this age is appalling. My own view is that there needs to be a bit of punishment element to discourage others. The way you actually win this argument is to use a technique that I deploy against say the NHBC for example. You might have a valid case for saying it's a structural safety issue. Then your case will get elevated up the chain. The structural issue is that if the pipe freezes water will potentially get into the structure and cause structural damage. You might argue that it might stain your flooring..but that is subjective, but as an SE if I argue the safety case they start to maybe wake up and smell the coffee. Karen, be persistent. What is happening here is gate keeping, they deny, delay, defend.

Historic bricks vary a lot in size, but that is the attraction. If the brickwork is essentially non load bearing then your options expand a lot. But BC might ask about their frost resistance. If they are particularly permeable then they may ask for a bespoke DPC type detail. It's horribly frustrating at times as a designer , especially when trying to recycle materials and do the right thing environmentally.

Call your SE and they may fix your dilemma. Why do you think the steels are oversized? What you are doing is actually quite complex and fraught with difficulty in terms of the fire design. Your SE is best placed to help.

Here is a bit of a good news story. There are two common ways of fire protecting steels. We can box it in with steel angles and say Fire Line plaster board or we can paint with intumescent paint. But BC often ask up front for a specification on the paint system. I wrote this morning to Rawlins Paints the following: Dear technical Department. I'm seeking assistance with a paint specification for steelwork fire protection and certificate / data sheets for a building warrant submission. Attached is a drawing showing the proposed steelwork. The project is a single story domestic house extension with a pitched concrete tiled roof in Scotland. The requirements are: 1/ Level of fire protection required 30minutes ( short duration). 2/ Section sizes are 178 x 102 UB19 S275 or S355 and 152 x 89 UB16 S275. 3/ The load ratio for the 178 x 102UB 19's is 35% and the load ratio for the 152 x 89 U16 is 50% 4/ Exposure to fire: Three sides are exposed; bottom flange and sides. The top flange has a 145 x 45 timber wall plate shot fired to it to support timber rafters. 5/ The beams are orientated in the vertical plane (top flanges upper most), loaded vertically downwards about their major axis. 6/ Quantities:The steelwork lengths are shown on the drawing. 7/ Steel design code is BS5950 part 1: 2000 8/ Exposure to weather: All steelwork is within the weatherproof envelope of the building. Thus dry conditions. No chemical exposure is required. 9/ Application of paint is to be on site, ideally brush applied. This can be done before fixing of the wall plates. By the close of business today I had a paint specification and an undertaking to supply the certification certificate provided we use their product of course. That is a fantastic service! Now for folk on BH. I'm putting these steels in awkward places, thus to box them in is going to be very labour intensive and that is very costly. On a technical note in item 3. I refer to what is called the load ratio. The steel sizes on this project are sized on how much they deflect in service. That stops cracking in ceilings for example. But in a fire we just want to make sure they don't fall down. The load ratio is the load on the steels in a fire compared with the steel beam ultimate strength / buckling strength. Long steel beam design is often governed by buckling, it twists and distorts first. That is why we tie floors into the steel beams for example to prevent the twisting in normal use. But during a fire that contribution can get lost as the floor / roof can burn away to the extent that it stops restraining the beams. Thus the load ratio is based on the strength of the beam when say part of the restraining floor or roof burns away in less than the required fire protection time. But even so using a paint system can be very cost effective. If a beam is not fully loaded up to it maximum capacity during a fire then the intumescent paint system can be of real economic advantage. To explain roughly. If a steel beam is loaded up to it's maximum capacity then it will fail at a lower temperature. A beam can still carry a bit of load at a higher temperature and that is where the load ratio comes in. The paint acts like an insulating blanket that slows the rate the steel heats up.. and that gives us the fire duration requirement we see in the building regs. The above it intended to give you a bit of a template if asking about intumescent paints.

Fair comment and accepted.

This is very well stated. It's part of Scottish humour, "ma sides are bursting". That means I'm chuckling a lot having read this, enough to hurt myself. One part of the meaning is to say that profit is sanity, turnover is vanity. A corollary could be the way a Yorkshire Farmer conducts business.

It's not the concrete strength I was remarking on it was the shrinkage and cracking. Anyway it's done now, time will tell if it becomes a serviceability issue. You're right in that it's ok to be sceptical at times on BH, there is no benefit to new members for example if we don't put forward different views. For me I expect folk to call me out if they feel I'm barking up the wrong tree. It's healthy to do so. But there is a caveat here. Some of the eco stuff and arguments are not adult and I have a limit on my time to address some of the nonsense promoted.

You are right in that a low offer can get folks back up. In some ways if you have a plot with fab views, location etc you know has sat for a long time then there is probably challenges associated with it. This sounds counter intuitive. But in some cases it can also work if you make a high, but broadly caveat initial offer This indicates you are serious about it and have already done you research "as a lay person". The seller can see you have spent some cash to date. The objective is to get them engaged and then lead them towards what is the true value of the plot. That could be to do with services, potential land contamination etc. The benefit of doing it this way is that once engaged you educate the seller to the point where they realise that they are not selling a Rolls Royce but a potential pup and might think, hey I'll just get rid of it as the purchaser (you) has explained the true value, the risk you are willing to take on. The selling agent will also see your argument and might say.. this is the best offer you are going to get. @Square Feet "The plot is owned by a limited company so I was able to find the owner's details including age and address. " As an off the wall thought. There may be a significant tax implication to the seller. But you'll only find that out and if you help them mitigate by getting them to the table.

@MikeSharp01 Interesting stuff.. Yes it can be, if you have the will to live. I think pragmatism should prevail here and, at times I'll just need to contradict myself! for the common good. What I was referring to was what happens in the walls of the house. To explain this in lay terms and to use a qualitative example. If you have good double glazing and say overnight the house is sitting inside at 18 deg C and the temperature outside drops to 10 deg C. The outside pane of glass may end up at 6.00 am in the morning at about 11- 12 deg. Now suddenly a warm moist weather front of air blows in. You can often see condensation on the outside of the glass. This happens quite a lot in Scotland for example. If you have rubbish glazing then the outer pane will be much warmer as it gets heated from the 18 deg C air inside the house and thus you are less likely to observe this. Now if you can see that then you might ask.. well are the walls that we can't see inside doing the same. That is in summary what I referred to as reverse condensation. But this thread is not really about that. It's to do with condensation inside the house when you cool it on hot days. The fundamental questions are: 1/ How cool do you want your house on a hot day and what am I prepared to pay for that? 2/ Am I going to do something that could compromise the design of the house. This could be by causing condensation to occur in a place where it can't be easily vented out and thus promote things to rot / corrode. We spend loads of time on BH detailing air tightness and so on.. but we are always thinking (so far until say this thread) from the inside out. 3/ Am I able to accept some cooling say from my Air source heat Pump (ASHP) and treat this as a bit of free lunch. It won't be perfect but it's a good pragmatic trade off. Now for me, take any underfloor heating / ASHP or similar combination. My immediate approach is to ask, can we keep it simple, cheep to maintain and by default retain value in your house. @JohnMo sums it up for me here with practical elegance. Aren't you going down a rabbit hole of complexity for complex sake. Heat pumps like simple open flow systems, if you involve UFH you are limited to 14 to 16 Deg flow temp (depends on location), no dew point management specifically needed. Size any fan coils to operate at that flow temp. Otherwise your into electronic mixers etc. In summary there is no perfect answer. The systems are generally set up to heat the house, but can cool to some extent. But for a bit of pragmatism lets look at what could go wrong if you get condensation on the heating pipes in cooling mode. 1/ If you lag the pipes then water gas will still get in and condense. If running for a long time with adverse humidity then water will collect and run out the gaps in the insulation. Now if that happens over a ceiling it will cause staining. 2/ Much depends on how you use and respect the house. If you are boiling up pasta big time or drying washing inside then that is an issue. The building regs are set up for this, but.. 3/ We need to consider the frequency of occurrence. It's ok if from time to time you get a bit of condensation, so long as you get rid of it quickly enough then the risk of harm is low. We will quite happily take a couple of buckets of water and wash floors! That will change the humidity rapidly.

I posted some stuff a few years back about how you get, call it " reverse condensation". My post was driven as I live in Scotland. Here we get days, particularly on the west coast where the house is cooler on the inside and the Atlantic Ocean moist winds blows in. Most BH folk wrote me off as a mad Jock! It totally reverses the dew point calculation and yes you do get condensation forming on the cooler house surfaces. Now in the south of the UK you are not accustomed to this.. but if you introduce air con into a very well insulated house then this kind of reverse dew point and internal condensation is worth a thought. In structural terms the odd bit of water gas condensation is ok.. but too much and you have a problem.

I'll take you word for it that they turned up with some lose rebar and made it all good. That requires diagonal bars to transfer the shrinkage loads around the service penetrations and supplementary bars to compensate for the cut ones. My experience tells me other wise. I doubt this happened, forgive my old school sceptesism, rafts and so on are not my first "rodeo!"

But the photo shows you have happily cut the rebar without reinforcing not least diagonally to prevent cracking. You've dropped a bollock there!