flanagaj

Hopefully, the diagram below will help. So it's easy to calculate ?, but a rafter is 6" or 8" and this will then throw the ridge height up by a given amount. So although measurement ? is constant so long as the pitch remains constant, then it does not matter whether you use a 100mm or 250mm rafter, however, the calculation fails to take into account the width of the rafter. And as I mentioned before, if I cut a birds mouth after I have calculated ?, then my ridge height will drop when I seat the rafter on the wall plate. You say I am over thinking it, but until I see an example of how I calculate ? with a given size rafter, a birds mouth cut and my ridge height being fixed, then I still don't get how you calculate it. The key point here, is that if ridge height is fixed then to maintain the same ridge height with a different sized birds mouth cuts or even different rafter sizes, the only variable that you have to change is the roof pitch. If I use a 100m rafter then my roof pitch will be steeper than if I use a 250mm rafter. Simply due to the fact, that bot ends would have to converge at point RH, but the 250mm rafter will sit higher on the wall plate than the 100mm rafter.

So I am perfectly fine at using trig to calculate the rafter length, eg hypotenuse of a triangle. But where my head is hurting is around the birds mouth cut. The depth of the birds mouth cut will drop the ridge by the same amount. And to therefore get the ridge height back to where it was before you cut the birds mouth, requires the roof pitch to be increased. What am I missing 🤯

Can anyone advise as to what the process is for increasing the size of the agreed sewage treatment plant to accommodate additional bedrooms? The approved planning app was for two bedrooms and we want to add a third one in the roof space. The architect has told us that this can be done as a minor amendment, but although 95% of the year the property will just be occupied by my wife and I, the other 5% might include our children and their partners. As a result, the occupancy will be 6 and the Graf system that has been specified is a 1-5 person system, and I am concerned that when everyone is home it won't cope with the load. The property sits in a nitrate mitigation area, and as part of the planning application they had to have a nitrate mitigation calculation done which calculated an average occupancy of 2.4 people. So this equates to a couple and a third person staying 146 days of the year. The nitrate mitigation credits have already been allocated, but if we increase the tank size will we have to get it agreed with planning and purchase additional credits?

I have sent you a pm. In a nutshell, we spent a fortune on the prelims for that property and we were disappointed that it didn't work for us. Happy to chat further off the forum though.

Fair point.

But where's the fun in getting someone else to do it 😄

I had no idea that these things existed. If you are planning on doing most aspects yourself, this looks like it saves a huge amount of time and makes excavation work much less error prone. Keen to get feedback from anyone who has used one. https://youtu.be/E9tb4b7rMb4?si=ddW3r1gnRJ1Og25s

This has got my attention. Did you do a simple hardcore / blinding / membrane / insulation / concrete floor and if so, did you do the pour? I have a large 157m2 slab and was planning on not having sleeper walls. Concerned that as it's quite large with a 7m span across the width, that it might be a job for a professional contractor. I had a quote from a reputable contractor, and it is was working out at £152/m2. That is for them doing the pour and then the subsequent polishing. If I could get that down to £120/m2 then I probably would just get them to do it. Will save a great deal of time not having to tile floors too.

So my current plan is to have the underfloor heating in the slab and then have the contractor power float it so it can be polished. This will negate the need for sleeper walls and then I can hopefully just build up the blocks directly on the slab. I suppose that this probably one for the SE to decide whether the slab is thick enough? I just wanted to ask whether anyone has done this as part of their build.

That's positive to hear. Having the estimate helps focus the mind as to where the money is spent, and it has helped me hugely in understanding what each stage costs. I have already saved a large sum by taking out the labour cost for decorating, fitting the external cladding and tiling the roof. So those savings can be used towards a nice kitchen and decent doors and windows.

So what about the situations where you intend on doing a lot of the work yourself as opposed to using a contractor to do the whole stage?

Nicely done! I'm very practical and would be open to that idea. Did you have any valleys, hips or roof lights?

Can I ask what you paid/m2 for installation?

So I received a quote for a seam sealed roof today and whilst the material cost seemed super reasonable, the installation cost made me take a lie down. it’s not a complex roof. 2 valleys, 2 small hips and 3 roof light. Approximate supply price per m² for GreenCoat™ PLX £23-25 + VAT Approximate supply price per m² for elZinc slate grey/graphite grey Zinc™ £35-38 + VAT Approximate installation price per m² £120-180 + VAT 120-180/m2 install cost? that only includes the breather membrane. Thoughts?

I found this image on one of the blogs, and I just love how the cladding is recessed back into the structure. Our proposed build is faced brick, 150mm cavity and the block. Is it simply a case that for the recessed part you would use the following layup. 18mm osb Vapour barrier 150mm studwork with celotex between 18mm osb Breathable roofing membrane Batten Cladding.. As the thickness of this is less than brick + cavity + block it is recessed back so that the osb is flush with the face of the internal block work.

House looks fantastic! I am really interested to hear the construction method that you employ for the cladding which is set back from the render. Is that section simply made using a SIP panel and cladded?

What was your cost/M2 for the concrete poor and power float?

It was around 1500/m2, and I am planning to do a fair amount myself too. The biggest cost is the planned clay tile roof. Labour and material are around 35k. Bungalow is 157m2 floor space. I am wondering whether there are other options as it’s currently working out at ~ £130/m2 i personally much prefer the seam sealed look

This what I had in mind.

I am not a fan of eaves, and am trying to understand whether I could dispense with them if you are having a clay tile roof. If you had fascia the same colour as your windows, I think this would potentially look very slick. The link below shows an image of what I am talking about. https://www.archdaily.com/952573/4-solutions-for-roofs-without-eaves-and-their-construction-details/5fc7ad6263c0179a2100009b-4-solutions-for-roofs-without-eaves-and-their-construction-details-image

Yes. Slightly.

I have just received my quote back from them. There were a few things to factor out from the quote. Builders profit, Site Manager cost ... I also noticed that I could get the 100mm sheets of Celotex at about £15 cheaper than they were quoting. Still going through the numbers, but it gives you an idea, and if you are requiring a mortgage to fund the build then it will most likely be required as part of the "I know what I am doing" check, rather than a finger in the air estimate.

This is very useful information. We are in the process of purchasing a plot with cash and will need lending for the build.

Another point is regarding costings for the build and what level of detail the lender wants to see for the mortgage application. Do they want fully quantity survey figures, such as those provide by estimators online, or is it just a case of providing less detailed labour / materials for each stage?

I received the estimators online quote back today, and I was quite surprised by the labour cost for the slab. Just going through the numbers to see where I could potentially save some money. 12k in labour sounds rather expensive. Ground floor UoM Labour Quantity Labour Total £ UoM Material Quantity Material Total £ Lay & compact MOT type 1 hardcore, delivered loose. Tn 43.148 2,021.23 Tn 44.000 1,409.86 Tool hire, plate compactor for the above task. > > > Dy 1.000 36.63 Sand blinding, delivered loose. Tn 14.383 524.03 Tn 15.000 481.13 Foil faced rigid PIR insulation board 2400x1200x100mm. M² 159.807 1,176.33 Ea 59.000 3,122.47 Polythene membrane, blue standard duty 300mu 100m2 rolls. M² 159.807 665.42 Rl 2.000 128.74 Polythene vapour control layer, blue standard duty. M² 159.807 998.13 Rl 2.000 128.74 Floor slab, cold bridge 200mm upstand M¹ 143.100 554.40 Ea 11.000 222.18 Concrete floor slab 100mm thick. M² 159.807 2,994.40 M³ 16.000 2,377.58 Tool hire, petrol power float for the above task. > > > Dy 1.000 45.79 Floor Screed, premixed delivered 1:3 mix. M² 154.038 3,347.12 Tn 24.000 3,228.49 12,281.06 11,181.61 This is the first time I've used estimators online, and I think I could have maybe been more specific. The floor plan had a kitchen with island shown, but they haven't put a kitchen in the quote or the utility room.