Jammy5

After a couple of really bad months on a personal level and also still not having my mortgage in place my build has ground to a bit of a stand still. However, I’ve managed to get free up some funds to keep something progressing, albeit at a much slower pace for a while. Whilst I await windows and doors I’m looking at the roof and room in the roof insulation and it’s here I need the advice of the forum members, or critique of my understanding of what’s on by building regulation drawings and also that within the SAP calc. Remember I’m on a traditional block build but I think it’s predominantly irreverent for this post. I’ve created the attached sketch showing my thoughts on what I’m being asked to produce within my build and I’ve colour coded for ease of explanation on what I’ve been asked for:- Red – 150mm PIR between rafters. Cyan – 63mm Gyproc Thermaline PIR Magenta – 12.5mm standard plasterboard Pink – 100mm PIR between vertical studs. Green – 38mm Gyproc Thermaline PIR White – Knauff Crown R40 Loft Roll Cross Lapped Dark Blue – 100mm Minimum, Acoustic soundproof quilt. The main area that’s testing my understanding is the vapour barrier or VCL which according to the drawings is only being asked for on sloping ceilings (and the dormers which I’ve left off this post for ease). From some research and my limited knowledge on the situation, it’s very difficult to pin down a specific and robust answer that whilst may not be perfect, at this point in life I’m looking for a…. is it “good enough” solution. Q1. It appears as though Insulated plasterboard such as Gyproc Thermaline acts as a VCL when taped and skimmed, is this correct? Q2. I’m struggling to find what product this is taped with, prior to plaster skim coat, to enable it to act as a VCL. Personally, I also can’t get my head around the insulated plasterboard acting as a VCL as its usually poly sheet or foil backed insulation with foil tape that creates the VCL. Q3. Any penetrations through the insulated plasterboard need to be sealed. However, what does this detail look like for back boxes and MVHR outlets that are positioned in the vertical wall in this space. Do I simply allow them to penetrate and use something like this:- https://www.ecomerchant.co.uk/instaabox.html?gad_source=1&gad_campaignid=21463137325&gbraid=0AAAAADf7paMA__cG_1DR9lzBewgHEVxEE&gclid=Cj0KCQjw9-PNBhDfARIsABHN6-1VRKNMyaBChEM-7t2A21FuIqThWTN5AM_dycJL21O7TmBHMYz_4nYaAjGzEALw_wcB and then use airtight tape around the MVHR pipe entry prior to the plaster skim coat If my understanding of Q1 is correct, as there is Insulated plasterboard on the face of the vertical studs and sloping ceilings then this will act as the VCL and this then only leaves the horizontal ceiling to find a solution. For the horizontal ceiling, its asking for 500mm of cross lapped loft insulation. I would then usually just put a normal 12.5mm plasterboard under this fixed directly to the joists. However, the complication comes that I intend on using the plaster in profile lights and the lack of VCL and air tightness. Q4. Is it as simple as using a polythene sheet on the underside of the joists, prior to boarding? The last part is the first floor ceilings directly below the cold loft space on the far left and right of the drawing that is lapped in 500mm of loft insulation. The set up will be the same as the horizonal ceiling on the second floor, that I will also be using plaster in profile lights. Q5. What is the best solution here, should I just use a polythene sheet on the ceiling of any rooms directly below this space? I’m just worried that it’s potentially not good practice to have a VCL between two warm spaces with half of the ceiling being directly below the warm room above. There are similarities to another post on the forum from this time last year here:- Correct method of vapour barrier installation - Heat Insulation - BuildHub.org.uk But it doesn't quite answer my queries. It’s probably also worth saying that the two sloping areas are a lot shorter than shown on the sketch, potentially only a few hundred mm each. Like I said, at this stage, I’m not trying to be perfect, I’m not trying to achieve passive house standards, I simply need to achieve my target of and 3m3/hour/m2 at a differential pressure of 50 Pa as per my SAP calculation. Buildhub Insulation Sketch.pdf

The SAP calc is asking for 63mm insulated plasterboard between garage and dwelling walls. Then for the ceiling it's 200mm R40 between joists and under drawn with 63mm insulated plasterboard and a layer of fire line board.

There's a note in the top right corner of drawing 3/3 that says in the circulation space on all levels (having read up I'm of the understanding this is the hall/landing etc). In addition, I will be placing heat detectors in the kitchen, utility room and garage as well for what it costs. Fire doors to each habitable room with intumescent strip which I'll be placing in the casings and I'll be putting the fire rated self closing hinges on them. The garage door is a bit different and specified with mechanical self closer, intumescent strips and smoke seals.

These are all of the drawings and were the drawings used to obtain Building Control plan approval. The garage isn't heated and is classed as a cold space from my understanding? What are you thinking here?

I have assumed I have the responsibility. The issue is, and maybe this is the biggest lesson of all. I've tried to split the works rather than just give the builder the primary contract and let them build from there. Someone who is used the building new build houses to the new standards. And this is where I come unstuck, the scope is to do the building work as per the drawings and recognised construction details.

Sorry I've been down tidying the site. Those are the drawings that were submitted for building regs approval and yes they were done by the current architect. I just need someone to advise where it's "shoddy", what needs resolved now and then specific details going forward for interpretation and how it is done in practice. Keeping an eye on the tradespeople or at least issuing them clear instructions on the details would also be good.

I will also be installing MVHR and UFH on the ground floor. Whilst these aren't identified in the SAP calc, I've now made them aware of this change

Good morning all, Please find attached the:- Architects drawings (JM 1A-JM 1C) Structural Drawing - Drawing 05-8876 01-02 mod B SAP Calc Hopefully I've caught all of the information when I've redacted. Important changes to note:- Structural Drawing shows a Girder Truss at the front. This was misinterpreted by the structural engineer. He has since confirmed that using extra heavy duty lintels above the two bedroom windows is acceptable with the current roof truss design. The two small Bi-Folds have been replaced with one singular 6m long Bi-Fold. This is reflected in the structural drawing but not on the architectural drawings. This has been agreed with BCO. SAP person is also on board and he believes some additional insulated plasterboard will compensate for the reduced cavity and insulation on the ground floor, rear elevation. The main part I struggle with is the conflict with the information contained within the SAP calc and that shown on the Architects drawings. Especially once I start following the recognised construction details that I need to achieve for the SAP calc (see link below for part fill insulation in the masonry cavity wall:- https://www.recognisedconstructiondetails.co.uk/walls/masonry-cavity-wall-partial-fill-insulation# Step 1 - 100mm Insulation (except on the rear ground floor, where it is 50mm) Step 2 - 0.022 W/mK Step 3 - 0.60 W/mK (Although I'm slightly better than this) Edit:- I should have explained my current build position:- Drainage all installed including attenuation tank in rear garden for surface water. All block/brickwork completed. 22mm flooring installed on 1st Floor. Roof completed with integrated solar panels & Soffit/Fascia. External cladding being installed on Dormers this week. Thanks in advance for this. Jamie drawing 05-8876 01-02 mod B.pdf JM 1A.pdf JM 1B.pdf JM 1C.pdf SAP 10 - Client Declaration of Agreed Construction Form Rev 0.pdf

Not at all, I was chuckling at your comment about needing money and explaining to my other half. The build is way more expensive than I ever could have imagined. I won't even break even, I'm expecting £540k on a £500k property but it is what it is. First things first as you say @Gus Potter, I need you guys to tell me where the big problems are and we go from there. One step at a time. Let me get these plans redacted and posted

Thank you this is crystal clear. I guess it's an issue I can't avoid now but the height of my window openings are 1220mm, therefore I can only get 1 run out of a 2.4m closer. Hence the much higher cost than anticipated. I was considering the calcium silicate board as it looked to be available in bigger boards but the other side I'm fighting with is the SAP calculation. My SAP guys wants me to follow the recognised construction details and for this it's demanding a barrier that achieves 0.026W/mK. Here's the link to the details: mpf-150-e3-01-cill_-proprietary-insultated-closer.pdf https://share.google/HmekAly15xvNh65mD Unfortunately looking at the calcium silicate board it's 0.15-0.17W/mK. The Timloc's are what I had looked at but they say they can't be joined. It's a nightmare.

Thank you for the encouraging words. My next challenge is VCL and Air tightness in the second floor and above the garage. This is my next battle and I will certainly need some help with this..... I bet it's the simplest thing ever if you've done it before. It's knowing exactly what to do and in what order. What I'm trying to avoid is doing something, and having to go back to rectify it a huge cost later on. I'll be honest, I'm at the stage where I wish I had just contracted the full build out.

Just so I'm clear, I'll check my contract with them tomorrow and specifically scope. Out of curiosity, for someone to act as the architect during the build stage, what is a general finger in the air fee? Or is this part and parcel of the support they should provide in completing building regulations drawings and consultation during this phase. As in the designer being on hand to answer TQ's?

I'm guessing there's no way of getting any money back for the lack of support? I just have to cut my losses and get someone else on board?

Thanks for the understanding. I'll grab the details tomorrow and post them on here with any personal details removed. Do I just post them in this chat? Or the introductions section?

I'll give them one last go before I do that bud. I'm really peeved off with the situation I've been left in, it's been the steepest learning curve of my life!