Spec my self-build!

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egomeister

Original Poster:

6,698 posts

262 months

Wednesday 14th August 2019
quotequote all
Ok, not exactly spec my self-build... more a request for information and inspiration!

I'm giving some serious consideration a self-build in order to get a house that best suits my needs rather than just pick from what is available, however this opens up a whole world of possibilities in terms of construction, layout, specification etc.

So, my question to the collective wisdom of PH is what features, products or even construction methods have you see that caught your imagination and would be in your fantasy (or reality!) self-build house?

Bob-iylho

694 posts

105 months

Wednesday 14th August 2019
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Quick reply, I did a self build 3 years ago.
Really pleased with it, but what everyone notices is quality of doors, windows, architrave etc.

So my advice is do not scrimp on the visual stuff. Plus stick to your budget, we were 10% over which is pretty good, but everyone will offer advice, do this it's only £2000, do this it's worth it for £5000, just stick to your plan unless you are desperate for it.
Our 10% went on better lighting, one additional bathroom and some more structural calculations and ammendments.

Chainsaw Rebuild

1,997 posts

101 months

Wednesday 14th August 2019
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I would make it the most energy efficient you can, both for the good of the planet and your wallet. Look into air source and ground source heat pumps for heating, your own borehole for water, solar panels etc. if you combined all of those you would hardly have any running costs relative to a normal house.

You of course need to have an excellent garage with enough height for a lift and a floor that can take it.

I agree on the quality of the finishing items. I forked out for a lovely floor and people notice it.

Also don't forget you can have the VAT back on self build materials.

egomeister

Original Poster:

6,698 posts

262 months

Wednesday 14th August 2019
quotequote all
Bob-iylho said:
Quick reply, I did a self build 3 years ago.
Really pleased with it, but what everyone notices is quality of doors, windows, architrave etc.

So my advice is do not scrimp on the visual stuff. Plus stick to your budget, we were 10% over which is pretty good, but everyone will offer advice, do this it's only £2000, do this it's worth it for £5000, just stick to your plan unless you are desperate for it.
Our 10% went on better lighting, one additional bathroom and some more structural calculations and ammendments.
Door and windows is one of the first things I noticed when looking at places with a more critical eye. Having a well sized high quality front door leading into a nice entrance hall makes a hell of a difference to how a place feels when you enter a house so this is already on my mental shopping list. I want to try to put together a realistic spec/budget so the compromises can be worked out up front rather than during the process - hence this thread! smile

Sheepshanks

32,541 posts

118 months

Wednesday 14th August 2019
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Have you got a plot lined up?

egomeister

Original Poster:

6,698 posts

262 months

Wednesday 14th August 2019
quotequote all
Chainsaw Rebuild said:
I would make it the most energy efficient you can, both for the good of the planet and your wallet. Look into air source and ground source heat pumps for heating, your own borehole for water, solar panels etc. if you combined all of those you would hardly have any running costs relative to a normal house.

You of course need to have an excellent garage with enough height for a lift and a floor that can take it.

I agree on the quality of the finishing items. I forked out for a lovely floor and people notice it.

Also don't forget you can have the VAT back on self build materials.
I'm definitely inclined towards an efficient structure, although perhaps not quite to passivhaus levels. From what I've read so far you can improve significantly over a "standard" new build quite economically, although as always the final gains cost the most.

I'll consider all heat / energy sources. As I understand it there are still incentives available so this can offset some of the costs.

egomeister

Original Poster:

6,698 posts

262 months

Wednesday 14th August 2019
quotequote all
Sheepshanks said:
Have you got a plot lined up?
Not yet, although I'm considering Graven Hill in Bicester so availability shouldn't be an issue and costs are relatively transparent. If I can put together a decent budget for the build side over the next few months I should be able to put together a realistic overall cost.

Shenanigans

2,964 posts

188 months

Wednesday 14th August 2019
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SIPs (Structurally Insulated Panels). Worked with them, specified them in the past and loved using them. If i were in the position to build my own house I'd specify the SIPs method of construction.

Equus

16,770 posts

100 months

Wednesday 14th August 2019
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Thermal mass.

Lots and lots of thermal mass (in the right place, of course).

If you're thinking about Graven Hill, start by reading the Design Code - you may discover that you don't have quite the design freedom you expect, depending on the location within the development.

egomeister

Original Poster:

6,698 posts

262 months

Thursday 15th August 2019
quotequote all
Equus said:
Thermal mass.

Lots and lots of thermal mass (in the right place, of course).

If you're thinking about Graven Hill, start by reading the Design Code - you may discover that you don't have quite the design freedom you expect, depending on the location within the development.
Presumably by thermal mass in the right place you are referring to the ground slab, but with high insulation & low thermal mass structures for walls to limit heat transfer between inside and out, managed with a MHVR?

In terms of Gravel hill, I'm aware that there are different areas that can be developed in different ways. I'm inclined to avoid those with a material palette, but nothing is set in stone.

Equus

16,770 posts

100 months

Thursday 15th August 2019
quotequote all
egomeister said:
Presumably by thermal mass in the right place you are referring to the ground slab, but with high insulation & low thermal mass structures for walls
Not necessarily, no: it can take a lot more than a ground floor slab to prevent overheating through solar gain, these days.That's the downside of very highly insulated but thermally lightweight structures like SIP and timber frame.

Personally, I would use a highly insulated SIP or TF structure with great care - and I'm saying that as ex-Design & Tech Director of a company that manufactured and sold them, so I'm not anti-TF... I just recognise that their lack of thermal mass can be a serious problem that you've got to design around with care, particularly if you want a lot of glazing.

Don't conflate high insulation with low thermal mass. The two are not inextricably linked.

Whitean3

2,182 posts

197 months

Thursday 15th August 2019
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I'd also advocate something energy efficient and with good insulation (we had a passivhaus built and moved in 1 year ago). But my suggestion for you to consider would be to include a basement level. Not at all common in the UK, I know.

But you can put a huge amount of storage, all your heating/technical equipment down there, laundry room too (built in laundry chutes are also great!) and leave all the above ground floor plan for living in, without worrying where to put massive wardrobes and without having to crawl into an attic.

Chainsaw Rebuild

1,997 posts

101 months

Thursday 15th August 2019
quotequote all
Whitean3 said:
I'd also advocate something energy efficient and with good insulation (we had a passivhaus built and moved in 1 year ago). But my suggestion for you to consider would be to include a basement level. Not at all common in the UK, I know.

But you can put a huge amount of storage, all your heating/technical equipment down there, laundry room too (built in laundry chutes are also great!) and leave all the above ground floor plan for living in, without worrying where to put massive wardrobes and without having to crawl into an attic.
I like this idea! you could have a cinema room/ loads of storge/spare room it also means you could have a "wine cellar" if your so inclined.

Another thing to consider is the technology you want in it and do you need network cable run in the walls/out to potential cctv points etc. Also if you are having a gate then run power out to it so you have the option of an electric gate.

s3dave

198 posts

157 months

Thursday 15th August 2019
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Build mine 2 years ago in SIPS - excellent for energy efficiency (strangely not so good on sound insulation). One thing I would recommend is MVHR, plus a large garage of course!

Equus

16,770 posts

100 months

Thursday 15th August 2019
quotequote all
s3dave said:
...strangely not so good on sound insulation.
No, this is another area where SIP/TF construction is frankly not good.

TF is better if you use mineral wool instead of PIR insulation (but of course mineral wool is then only half as good at thermal insulation as PIR, and you don't have that option with SIP because the foam is serving a structural function of stabilising the the skins against buckling).

But with some sound frequencies, there is no substitute for good old-fashioned mass.

egomeister

Original Poster:

6,698 posts

262 months

Friday 16th August 2019
quotequote all
Equus said:
egomeister said:
Presumably by thermal mass in the right place you are referring to the ground slab, but with high insulation & low thermal mass structures for walls
Not necessarily, no: it can take a lot more than a ground floor slab to prevent overheating through solar gain, these days.That's the downside of very highly insulated but thermally lightweight structures like SIP and timber frame.

Personally, I would use a highly insulated SIP or TF structure with great care - and I'm saying that as ex-Design & Tech Director of a company that manufactured and sold them, so I'm not anti-TF... I just recognise that their lack of thermal mass can be a serious problem that you've got to design around with care, particularly if you want a lot of glazing.

Don't conflate high insulation with low thermal mass. The two are not inextricably linked.
Equus said:
s3dave said:
...strangely not so good on sound insulation.
No, this is another area where SIP/TF construction is frankly not good.

TF is better if you use mineral wool instead of PIR insulation (but of course mineral wool is then only half as good at thermal insulation as PIR, and you don't have that option with SIP because the foam is serving a structural function of stabilising the the skins against buckling).

But with some sound frequencies, there is no substitute for good old-fashioned mass.
Some useful info here, thanks. I'm not really thinking of vast areas of glass as I think it would be over the top without a large garden or countryside views to use it with, but possibly closer to what would have been seen in 60s/70s build rather than what you'd see on a current developer estate build. Obviously I would be relying on better performance of the windows to mitigate the increased area, and take on board what you are saying about solar gain.

I assume this is why on high efficiency builds you often see a move towards the use of things like air source heat pumps, as they provides the ability to manage temperature both ways?

I hadn't considered the effect of insulation in terms of sound deadening. I've looked briefly at a couple of kit systems, one using foam and one using mineral wool although I did spot that they used a different grade of mineral wool on internal walls that is better suited to sound deadening.

egomeister

Original Poster:

6,698 posts

262 months

Friday 16th August 2019
quotequote all
Whitean3 said:
I'd also advocate something energy efficient and with good insulation (we had a passivhaus built and moved in 1 year ago). But my suggestion for you to consider would be to include a basement level. Not at all common in the UK, I know.

But you can put a huge amount of storage, all your heating/technical equipment down there, laundry room too (built in laundry chutes are also great!) and leave all the above ground floor plan for living in, without worrying where to put massive wardrobes and without having to crawl into an attic.
Having spent some time on the continent where apartments with communal heating systems and basements are much more common I certainly appreciate this, but I think the cost would be well beyond me at this time! Nice idea with the laundry chutes too - this is exactly the kind of thing that could be planned into a build, but impossible to incorporate later!

egomeister

Original Poster:

6,698 posts

262 months

Friday 16th August 2019
quotequote all
s3dave said:
... plus a large garage of course!
This was the starting point that led me down the rabbit hole of investigating possibilities for self-build. biggrin

anonymous-user

53 months

Friday 16th August 2019
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You mention Graven Hill, I assume you have watched the GD series on it?

Might be worth a watch if not, think at least one person used SIPS

GliderRider

2,071 posts

80 months

Friday 16th August 2019
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Whitean3 said:
I'd also advocate something energy efficient and with good insulation (we had a passivhaus built and moved in 1 year ago). But my suggestion for you to consider would be to include a basement level. Not at all common in the UK, I know.

But you can put a huge amount of storage, all your heating/technical equipment down there, laundry room too (built in laundry chutes are also great!) and leave all the above ground floor plan for living in, without worrying where to put massive wardrobes and without having to crawl into an attic.
My parents built a house with a basement, starting in the 1960s, after visiting Canada and seeing the benefit of them there. They built the house in a gully, which meant one end was underground, with the other at ground level, so the entrance to the garage above the underground end, whilst we had ground level access in and out at the other, it also limited the amount that had to be dug out. The dug out earth was placed next to the house and leveled to give the lawn once the building was finished. The central heating boiler was in the basement, which helped keep it warm in winter.

In the double garage there was a pit which was really just a hole in the roof of the basement. It did mean you could go from underneath the car to the workshop (also in the basement) without going outside. Dad's interests when he started designing the place were gliding and sailing, so the basement was designed to accommodate a 15 metre glider wing in one piece (helpful for alignment when doing repairs), and the pit was designed around lowering a 14ft sailing dinghy through it for storage below the other side without the pit.

Constuction of the house was breeze block below ground level, with reclaimed brick above. Stone buttresses were used on the corners. The roof of the basement was woodwool slabs with columns of reinforced concrete cast in open ended 5 gal oil drums which were cut off afterwards. In addition to the reclaimed bricks, a lot of the wood was salvaged from Victorian Army barracks which were being demolished at the time.