Indy

I’ve posted on the topic of active cooling before but the responses were quite limited, and only about running your ASHP in reverse. I understand this acts more like a trim function rather than a true active air con system. What I’m after is similar to the HVAC systems found in offices - where you enter a room and there’s a thermostat by the door. Set it 20c and the air con kicks in, set it higher and the heating kicks in. Does something like this exist for the residential market, by which I mean at reasonable prices? I’ve heard of MVHR systems where you can utilise the ducting for active cooling - maybe a hybrid system I’m not aware of?

This is new to me - Preliminary Desktop Study for what exactly, out of interest?

U-values: Floor: 0.18 Walls: 0.18 Roof: 0.15 Link to the doc here - https://www.gov.uk/guidance/building-regulations-and-approved-documents-index#approved-documents

What online service are you planning to use?

A topic I am very interested in myself and have been trying to get a comparative cost to see what would be cheaper. From speaking to the architect, a few things that came out: Concrete floors - either beam and block or hollowcore will be quite thick and need a further void put in to run services/MVHR ducting. This may be an issue and reduce available head height in the rooms if that's a constraint for you. Concrete floors will also add to the weight of the building naturally and may mean more substantial foundations or SE designs. Will also cost more. Timber floors - in the form of metal web joists are the usual option and offer flexibility in the sense that the ducting can be run through quite easily. One option that's been put forward as a halfway house is a Lewis/metal deck on top of the timber floors with a concrete screed on top of this. Offers the best of both without increasing floor makeup too much. I've not seen that before so would be interested to hear from anyone who has gone for that setup?

London prices always seem to be in their own little world and bear little resemblance to what the online guides or even SPONS will tell you. However, that price does seem extortionately high. 60 sq m at £3k per sq m gives you £180k. I've deliberately chosen that number as most people seem to be self build from scratch at £2k, though I've factored in access restrictions and the higher costs due to it being a basement flat. Even at £4k per sq m - you only get to £240k, which is still lower than your lowest priced quote. I'm sure people dig out basements from scratch and then finish for £4k per sq m, so your refurbishment job should be a lot cheaper really.

The one thing I've figured out in all this process is that no matter which build system I use, market forces will collude against me to make that the most expensive at the time! We were originally considering timber frame a year ago and at the time - timber prices were through the roof and going through 10% MoM upward revisions. We then moved to consider ICF but were told by everyone that concrete prices are too high because of rising energy costs to make the stuff blah blah. Finally came round to bricks and blocks as the prices had been stable for about 2 years - guess what, just started to rise again 😣 Also perfectly correlated with my putting part of the build fund in crypto at the start of the year thinking - surely I can get a better return than the paltry 1% I was getting in a savings account. Turns out, I can't 😤 I'm sure I've posted the plans in one of my earlier posts but its an 8m x 5m building that is split 75/25 between a gym and a storage area/workshop. It is specced in the same materials as the main building now but the quotes have assumed a lot of unnecessary things like UFH, expensive glazing and A2A heat pumps. Easy way for me to drop 10% off the build budget and maybe build a log cabin structure instead - which should come in at less than £20k with a few bells and whistles.

Coming back to this thread after a long time, but I thought it's easier to do it here rather than start a new one as there's lots of useful replies here already. Combing through the quotes I've had back from the TF companies, its virtually impossible to do a like for like comparison as they all operate slightly differently. I did get a paid for quote from Estimators for a masonry build, a full turnkey quote from a Nudura ICF builder and a 'finger in the air estimate' from a local builder who's done some work for our friends and is generally well regarded in the area. A few thoughts after some detailed discussions with a number of companies more recently: The feeling is that material costs will stabilise but not necessarily drop, just the monthly increases will come to a bit of a halt. Labour prices may drop due to the pending recession and cost of living crisis. A lot of people simply can't afford to build anymore due to the skyrocketing costs, which means that companies may be forced to cut labour rates to stay afloat (I can certainly dream!) The architect's recommendation is to build in standard masonry, and he's confident that we can achieve the thermal efficiency and airtightness of modern methods of construction. Obviously harder and needs constant monitoring but certainly not impossible. Local builder that has done work for friends and is also doing some work for us currently gave us an estimate that comes in around the £2k/sq m mark (masonry build). This would be full turnkey service including demolition, foundation and all the associated works to finish the property. One thing that we can easily drop from the build is the outbuilding as the costs for that range from about £38k to £96k(!). A cheaper timber shed may have to suffice for now and we can add a more permanent structure in the future.

The turnaround was quick enough - 3 business days though I was relatively unimpressed with their service. A lot of standard things have been left out including glass balustrades, guttering, flat roof decking, MVHR, Solar PV. Not sure what I was expecting, but I guess they had limited information to work off of (without building drawings). Pleased to hear that your plans were approved. Ours are due to come through within this week and I can't wait. Seems like a long and arduous journey and it has been over a year since we bought the place to even get to this stage! And glad that you got on well with the architect. He's one of the few people that are both knowledgeable and keen to help. With most others that I met with and reviewed our plans, I have no doubt that they had the experience to deliver but getting any information out of them is like getting blood out of a stone. God knows I've tested our architect's patience on more than one occasion but he has always helped us out and set us on the right path, so no reason for me to complain. Price wise, he said the same to me (£3500/sq m) which actually prompted one of my more discussed posts on the costing forum. It's actually not too far off from reality if you choose a complete turnkey build as I've had quotes in that region though our budget doesn't stretch that far. Plan is the same as yours - to try and bring it in at about £2000/sq m, which is just about manageable.

Good point about airtightness - what value should we be aiming at ? Noted and we can play about with the type. PIR was the default option recommended by the architect. Ok, I thought each of the rooms would be configurable using their own thermostat but it sounds like the systems runs at a single temp overall. Mainly for noise insulation. If we're going concrete walls, may as well go concrete floors and blockwork walls was my thinking. However, I should be able to derive the cost difference by comparing the quotes from Options 1a and 1b. I have submitted to Estimators now, and the prices for each option have shot up dramatically (should have expected that). When I spoke to them over the phone prior to submission and payment for 1 option, it was very simply £190+VAT for the first and then £90+VAT for every subsequent option you want to price. It's now gone up to £165ish for every variant, another £165 for the outbuilding we want to build and a full £228 for the timber frame variant - due to the 'amount of work involved'. This meant I've pared down significantly what I'm asking them to quote and only getting costs for Option 1a and 1b (i.e. compare between timber and concrete internals).

They came as a recommendation from the architect. Compliant to building regs (as I've been told) and within 7-10% of the PH spec without going all the way - and incurring the extra expense.

Request is in with Estimators, lets see what they come back with. They aim to reply by next working day which is pretty a impressive turnaround - given that most TF and ICF companies seem to take a couple of weeks minimum to quote.

So things are finally moving ahead with our planning. Had a site visit from the planning officer last week and we may be hearing in the next couple of weeks with a final decision. Which also means that discussions with my architect have finally started about the 'how to build' stage. All my online research was pointing to ICF and while he's happy to do the next stage of drawings and prepare a spec for that, his view is that will definitely cost more than doing it in standard masonry or even timber frame. And my preferred option of concrete floors vs the timber floors/metal web joists will push up costs even further. What I've agreed is that we get 'high level estimates' from the likes of Estimators Online or Build Aviator (Jewson) on the 4 options Option 1a: Masonry build (block and block) with timber floors/metal deck and oak staircase Option 1b: Masonry build with concrete floors and concrete stairs Option 2: Timber frame with timber floors and oak staircase Option 3: ICF build with concrete floors and concrete stairs Speaking to Estimators online, they're happy to quote for the masonry option and timber frame, but not ICF. Obviously, every variant will be added cost (not about half the price of a full quote) but I'm hoping this initial analysis will allow us to select the best build method for our budget and then proceed to the next stage and draw up the building regulations drawings accordingly. The TF quote will also allow me to compare it to the actual quotes received from the companies I contacted (MBC, English brothers, Fleming, Scandi-Hus) to see how much of a markup there is between them. In addition to the planning drawings, I've drawn up the following high level spec/information that I will be including in my request. Is there anything I've missed out and should be specifying? Common areas Compliant to Building Regulations that came into force on 15/06/2022 U Values for walls: 0.16 U values for floors: 0.11 U values for roof: 0.11 Wall thickness as planned: 350mm 3 phase electric supply ASHP for the main house that can also run in cooling mode UFH throughout (ground floor and first) with individual thermostats MVHR Solar PV Electric vehicle charging points x 2 Data cabling (2 x CAT6) to each bedroom (x 4), snug, study (x2), living room, dining room and kitchen 2 x satellite connections to each bedroom, snug, study, living room, dining room and kitchen 2 x terrestrial (freeview) connections to each bedroom, snug, study, living room and dining room and kitchen Cabling for a wired security alarm and CCTVs (PoE) on all 4 corners of the house, cover the front drive/gate, cover the rear garden and outbuilding. Data and power cabling to the rear outbuilding (gym and storage/workshop) Vaulted ceilings in the master bedroom and bedrooms 2 and 3 Good acoustic insulation between floors and rooms to stop noise travelling through LVT flooring on ground floor living areas and study Engineered wood flooring in Bedroom 1 Engineered wood flooring on 1st floor bedrooms and family snug Silicone render finish outside – crisp white Ducting and power connections alongside MVHR for active air conditioning to be added in the future to the bedrooms and main living area Alu-clad triple glazed timber windows in grey Alu-clad triple glazed sliding doors in the kitchen/dining areas with slim frames and for the master bedroom Glass balustrade for master bedroom balcony uPVC fascia and soffits in grey uPVC rainwater goods in black Timer/timber effect infill panels for the front elevation Plain clay roof tiles in grey External tap provision on the side of the house near the front – washing cars External tap provision on the side of the house near the rear – watering/gardening Large outdoor sink near the rear – washing the dog/muddy boots etc Option 1a: Block and block construction with timber floors Block and block construction filled with PIR to achieve the required U values Timber floors with metal deck and noise insulation Metal web joists to allow ducting of services and MVHR Oak staircase Timber walls / stud walls for internal rooms with noise insulation Option 1b: Block and block construction with concrete floors Block and block construction filled with PIR to achieve the required U values Concrete floors – slab/beam and block/hollowcore with embedded UFH in the screed Concrete stairs (pre-cast or in-situ with shuttering) with wooden covering Concrete blocks for internal walls with plaster on either side Option 2: Timber frame with timber floors Timber frame shell with insulation provided and erected by a supplier on site to meet the U-values as specified Timber floors with metal deck and noise insulation Metal web joists to allow ducting of services and MVHR Oak staircase Timber walls / stud walls for internal rooms with noise insulation Option 3: ICF construction with concrete floors ICF walls to achieve the U-values as specified using Nudura or Thermohouse (EPS system) Silicone render on the EPS layer in white Concrete slab floors with UFH embedded on both floors Concrete stairs (pre-cast or in-situ with shuttering) with wooden covering Concrete blocks for internal walls with plaster on either side

Welcome to the forum. Which part of London are you in, and if you don't mind me asking - what cost / m2 are you looking at having re-tendered?

Interested to hear what the outcome was, and how much of an actual uplift you saw compared to Jan 2021?

For those that have used UFH in their builds, do you use the same wet UFH throughout or do you split the bathrooms to have electric UFH (i.e. switch on when needed)? Also, I assume that each room temperature is controllable using dedicated thermostats or can you only have 1 temperature set at the master control and through the house?

I'm in a similar boat to you - new build house though with concrete walls and most likely concrete floors. However, I'm much more pro UFH as I hate radiators - mainly for the space they take up on walls and the fact that you can't really use that space for anything else. I did also have questions around maintenance of UFH, especially if you're burying these within your concrete slab. The conversations I've had with loads of people assure me that failures are quite rare, and probably no more messy than sorting radiator pipework. The bits I haven't completely figured out are whether we go for UFH throughout (i.e. on the upper floors as well), how to use the ASHP + UFH for some sort of cooling effect and finally, wet UFH vs electric UFH in the bathroom areas.

Are you building with Thermohouse @Nick Laslett? Would be very interested to hear more of your experience as its something I'm looking into.

So render over the EPS ICF is waterproof enough? How about structural rigidity - i.e. if you hit the side of the walls with a hammer or something heavy, would the EPS crumble or get dents? Or does the render 'harden' and provide a protective layer?

There have been a few of these on the forum recently, but rather than hijack those - thought I would start my own as my query is slightly different. Fairly settled on going for an EPS type system - either Nudura or Thermohouse (if I can afford the latter!). Wanted to understand the options there are for both internal and external cladding. Internal - fairly straightforward in the sense that we'll get plasterboard and then normal plaster and paint on top. Would this be a sensible approach to have an airtight home to almost PH levels, that work with MVHR? Would the plasterboard wall be strong enough to take the weight of usual fixings on the wall (discounting the kitchen units, where I've been told we can put up an OSB to take the weight). External - this is more confusing. We're going for a white render finish and the recommendation from both companies is to render directly on top of the EPS (with the usual base coat applied). Even with the silicone render and the hygrophobic properties that are touted, I'm not sure I trust this enough to not have a proper rain screen. We're not going for a timber clad look, its smooth render on the majority of the building. What are the options here - something like fireproof cement board and render on top of that? Something else that I'm not aware of? Or am I being too pessimistic and render on top of EPS is sufficient? Pics for reference https://ibb.co/k1tHrNX https://ibb.co/vj1hnm1

Thermohouse is one option where they offer solutions for walls, floors and the roof - all based on their own system. When I've enquired (no practical experience unfortunately) - have been told that it's possible to fix directly into the EPS on both Nudura and Thermohouse blocks, as they add reinforcements within the blocks to allow this.

So quite a range of opinions. We will be taking some, but maybe not all of our current furniture along with us as I want to start fresh in the new place. What I don't want is to take all of our existing stuff along which means the house becomes a hotch potch of styles. I'm still considering going for the design only service, and not actually asking the interior designers to do any purchase or sourcing. That way, I have a list to work from, as funds allow in the future. Also taking a lot of notes and inspiration from all the different sites, actual houses, showrooms, magazines, TV shows etc and will have a pretty clear idea of what we like and don't like. Quite a lot of the rooms will end up being designed in the house anyway - bathrooms, kitchen, utility and by extension the dining/living areas. Its mainly the bedrooms and studies in the house that we would consider getting advice on.

The one that we like the look of does lighting design as part of the interior design package, so that's a good sign. Another is that she's fully booked out for the rest of 2022 which isnt an issue for us but points to how popular these services are becoming I guess.

This is why I would source and do the actual work myself. Not going for a full hands off approach where budget is of no concern. Essentially paying for a 'design only' service that gives us a palette of colours/materials/furnishings to choose from and we can do the final tweaking to our tastes. There seem to be a lot of sites that are now offering this kind of service, even IKEA is in the game offering online interior design.

Where was this when we were crafting our design brief a year ago?! Really helpful and bookmarked for future use - thank you for sharing As to the original poster, once the excitement of having secured the plot wears off.... it's all downhill from there 🤔