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Hello Everyone! I've been following BH for almost a week now and am gobsmacked with the knowledge and helpfulness of all you kind people.... So here I am, hoping to learn (and in time, perhaps contribute) to this wonderful community. This is a long read (sorry!) We have planning permission to convert a shed into a 4-bed house in Kent. We've brought in mains water and electricity. There is no connection to gas or sewage. The barn sits on a cement foundation which we will retain. The main double-height shed is made from a pre-cast concrete structure (to keep). The 2 lean-to single storey structures on either side are built on steel beams (again, structure to keep) I am in charge of this project as I have the time and *some* experience with small renovations (extensions and loft conversions). My husband's work keeps him busy and out of trouble for the most part (it's my dream to build our home that got us here!!). We're very happy with the design drawn up by our architect. My challenge is to translate that design into a build we can afford. The QS (first pass, Stage 3 level) has come up with an astronomical build cost - more than double of what our brief to the architect was! Some serious value engineering along with compromises have to be made to keep costs down. We are prepared to part-build - focus on the main shed and west lean-to, leaving the east lean-to and landscape for a later time. Overall, we want to take a fabric first approach and make the home as low-energy and sustainable as possible (near Passivhaus standards). We would like to engage a local contractor in Kent (any suggestions would be most appreciated; we live in London, 1.5 hrs from the barn so don't know the local area well) Would it be cheaper to have the groundworks done by the local contractor, then bring in a Timber Framing company (Frame Build UK?) do the build before passing it back to the local contractor take charge of the rest? What hybrid model (if any!) would be best? What professionals are essential? Our architects suggests... - Building Services Engineer for heating/cooling/electrics.... We're keen to install ASHP (with UFH), MVHR, Solar PV (under PD, so just 9sqm), (Tesla?) battery storage. And they all need to talk to each other! Can a one-stop shop (e.g., Better Planet or Total Home Environment) who supply, install, and commission be a good substitute for a Building Services Engineer? - SAP consultant - we have one who can also provide Airtightness Testing if needed - Civil engineer to specify the sewage treatment plant... Again, can the folks at say, Graf be just as competent to specify the duct/pipe design? - Structural Engineer - already engaged - Building Regs Inspector - already engaged - QS - already engaged for first pass... We will likely need a Bill of Quantities before going out to tender. And wonder if using ProQuant would be more cost effective So far, Roof and Wall insulations have been specified.....Is there a way to gauge how close they will be to Passivhaus standards? Does there appear to be room to reduce costs here? Roof Insulation 1. Form new roof structure comprising; allow 150mm timber joists with 140 thick Rockwool Flexi insulation between joists; 12mm plywood decking; 100 thick Rockwood Hardrock insulation; breather membrane; form 50mm ventilation space from timber battens. 2 Fibre cement corrugated roof finish Wall Insulation 1 New external wall structure, comprising; 150 thick timber studwork structure with 120 thick mineral wool insulation; 12mm WBP ply; breather membrane; 50mm metal studs to form ventilation gap; vapour barrier and 25mm Rockwood RWA slab on 25mm timber studs to internal face; 2 Corrugated cladding; 3 Timber perforated screen on 50mm studs; 4 Insulated render Apologies for the long read and many questions! Any help, guidance, advice, will be deeply appreciated. Many thanks! L09P-Proposed Cross Sections.pdf L08P-Proposed Roof Plan.pdf L07P-Proposed First Floor Plan.pdf L06P-Proposed Ground Floor Plan.pdf L06P-Proposed Ground Floor Plan.pdf L07P-Proposed First Floor Plan.pdf L08P-Proposed Roof Plan.pdf L00-Cover.pdf