jen and mark

Love a bit of tantalised wood! Cheers guys, will get a new designer - not happy with this one but he has been seriously ill - think he was in his prime in the 80s! Many thanks PS sorry uploading it that way - didn't want the full address and names on the web and couldn't sus out how to upload without.

This was our original sectional drawings - no mention of any thermal issues or airtightness!sectional design.pdf

Just popped in to make a cuppa - horrible weather! Will post sectional drawings tonight. Cheers

Many thanks for the info. Background experience - several large barn conversions (working for a traditional builders firm) of stone and timber in the Cotswold - carpenter by trade. So much easier than steel! Unfortunately, our designer has been diagnosed with cancer and undergoing treatment which, rightly so, has meant he is unavailable. This was something we had not foreseen. We are now in a dilemma - do we instruct some one new? Wait and hope he makes a speedy recovery (of course) or try and manage with help from you guys!!!!! As always with self build, budget is a major constraint - the barn is very large which in itself means more materials and we wont mention the current state of affairs with materials and prices at the moment! More late night researching - if not, get used to caravan living!

Ok - lots to think about here. Steel is not my area of expertise as you may have guessed! Would this work: - Vapour/air barrier - walls having similar composite cladding to roof all round - 40mm PIR core with a u Value of 0.46 - (minimal wooden cladding with similar insulation behind to break up the steel box effect) Not sure how to make where the walls and roof meet airtight - tape? Second internal stud wall insulated to 0 . 21 w/ m² k - airtight with vapour/air barrier - or am I fighting a losing battle here? Thanks for any advice!

We hope to mitigate this by having a large overhang on the roof so the outside walls meet the roof on the outside of the frame.

Great advice @saveasteading. We are thinking of using http://sasprojects.com/roofing-cladding/ They are a commercial company rather than domestic - we met them at our storage facility as they were adding another self storage unit, but do do domestic as a bit of a side line. They design and fabricate all of the steel work in their workshop. We have had a quote of £45,000 for the roof (354m2), insulated valley, hopper etc and includes telehandler and installation etc. This works out at approx £127m2 but the roof would be complete - no need to plasterboard or plaster inside so seemed a good option. We are still debating the wall cladding! Many thanks

Could you clarify which bit is nonsense - is it the condensation issue or the MHVR. Would you clad all the columns or would it be ok to expose any? My thoughts are the steel would be inside the envelope even though the outside steels would have limited insulation. Have you found the composite roofing system ok? Love the bituthene liner - bit expensive though! Will look forward to anyone else's view on this Many thanks

Good morning, We are in the process of converting a double steel portal barn and are considering having a steel composite roof to u value 0.15. As I see it, the pros would be: Complete roof - quick to install No thermal break - the steels would be inside the thermal envelope We could expose the steel purlins in our vaulted roof - giving a nod to its agricultural heritage cons: Condensation - condensation on the steel frame, and possibly forming within the walls. So my question is has anyone ever used these composite steel roofing panels as the final finish internally? The construction is..... We have raised the original floor by approx. 420mm - usual hardcore (MOT type 1), blinding and DPM - Gen 3 with fibres being poured on 23rd August. This meant we did not have to dig out the already solid base. We have a single skin block wall ( about 4ft high) between the steels which we will add a timber stud on top and then add a second timber stud wall, internally, to create a cavity, we will insulate (to building regs) the 2nd stud wall. The outside will then be clad with a combination of steel and wood cladding with nominal insulation to avoid heat losses through the steel frame. We will always have a problem with cold bridging from the floor as the steel stanchions have no thermal break on the pads. Our plan is to wrap the bottoms of the columns in Celotex, where they came through the floor, to thermally break them from the insulated slab, that includes the UFH. A tip given by @IanR. Any help would be appreciated!

Thanks for this - I think we need to seriously consider our options - luckily we are still in the early stages!

The roof panels are Kingspan with a u value of 0.15 - well below the regs of 0.18 which is why we thought it would be a good idea plus the underside of the panels are the finish so no need to plasterboard and can keep the vaulted ceilings to the hall, kitchen, lounge and bedrooms (although we will have standard ceilings in the bathrooms, ensuites, utility etc to accommodate the MHRV ducting) We will also have insulation, vapour, air barrier and cladding externally on top of the steel and block walls. This will be minimal though as we cannot go (much) beyond the original footprint so we are insulating the inner skin to building regs. The external insulation is a bonus and to help with thermal bridging. I know - what a nightmare and I cant think of a way around this - we are deffo NOT going to dig out the pads to put in thermal breaks! I do like your idea of wrapping the steels to UFH level. We are currently living on site in a mobile so hopefully the barn will be warmer that this is in winter! Hopefully the insulation wrapped outer steels will mitigate this Great idea-will do Many thanks for your time and knowledge

Thanks for the info @IanR Thermal bridging is a nightmare for steel framed building! On one side of the barn, the purlins are wood and on the other side (double barn) they are steel z purlins. The columns will not be visible from the outside and will have some insulation outside and more in the internal stud wall. The 'saleperson' regarding the composite roof informed us that the roof would be more thermal efficient as there would be no thermal break. When I asked about condensation he said the MHRV would sort this out. You have me worried now! Great tip about wrapping the columns in celotex - we will definitely do this!

Thanks @saveasteading I think you are right regarding pads and SE The DPM below slab is 1200 gauge Visqueen Ecomembrane Damp Proof Membrane ( polyethylene). I will look in to the bituthene - is it like tanking for a cellar? Would you install before the concrete is poured? Cheers

Thanks very much for the prompt replies! Luckily, our barn was built on sufficient pads and the SE was happy for no more additional work. The double barn was erected in 1990. We are having a steel composite roof so we can expose all the purlins and some sides of the main frame/columns. We have no other properties around us apart from a neighbours shed - our barn is 4.5m from the boundary fence so the BI is not too worried about the spread so because of this, I didn't say anything more but did wonder of we needed to treat the exposed steel with the very expensive intumescent paint! The construction is..... We have raised the original floor by approx. 420mm - usual hardcore (MOT type 1), blinding and DPM - Gen 3 with fibres being poured on 23rd August. This meant we did not have to dig out the already solid base. We have a single skin block wall ( about 4ft high) between the steels which we will add a timber stud on top and then add a second timber stud wall, internally, to create a cavity, we will insulate the 2nd stud wall. The outside will then be clad with a combination of steel and wood cladding. Another question - would you cover the existing block wall (no existing damp proofing) with the same visqueen that is going under the slab and then add a DPC on top before we build the external stud wall? Many thanks in advance

Good afternoon! We are in the process of converting a double steel portal barn in to our new dream home. I have a quick question that I hope you guys can shine some light on. Looking at Part B, fire regulations, do we need to paint our frame in Intumescent Steel Paint? It is a single storey, single dwelling. Many thanks Jenny

Hi Guys, new to site as we are about to convert a steel barn to residential. Its very rural with no services (should be happening in 12 weeks) and winter coming! We will be living in a static so if anyone has any tips, please let us know! Cheers jen and mark