ProDave

Hello fellow Scottish builders

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Hi Dave,

Yes, spoke to builder yesterday - he was planning to use Scotframe for the kits but they've let him down so he's going to use his own Polish crew of carpenters to build the frames - he's pulled the timescales forwards because there's a risk of an 8-week shutdown over Xmas/New Year (4 weeks break + 2 weeks quarantine either side). 

Luckily we're fine for accommodation (apart from being a long way from Mull) and we'll probably be rat and mouse free by then! (fortunately they're in the roof, not in the house) but it gives me something to do ūüôā

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Hello Scotland. I'm outside Edinburgh in Balerno. Just got planning after ten months. The next hurdle is a mortgage - was hoping to do ICF, Zinc and Larch cladding. But having spoken to Buildstore they are coming back with just the Halifax. Who won't lend a sensible amount of money. Maybe it's based on being self employed rather than the rona... Any suggestions would be gratefully appreciated.

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30 minutes ago, Firsttimer said:

Any suggestions would be gratefully appreciated.


Quite a few people on here have used Ecology. 

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4 minutes ago, newhome said:


Quite a few people on here have used Ecology. 

Thanks. it's a bit pesky that they need to know the SAP ratings before talking to you properly. Am going to give them another call tomorrow to try and find out if they would at least lend on the materials.

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12 minutes ago, Firsttimer said:

Thanks. it's a bit pesky that they need to know the SAP ratings before talking to you properly. Am going to give them another call tomorrow to try and find out if they would at least lend on the materials.


Scottish Building Society is mentioned in this post. 
 

 

 

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1 minute ago, newhome said:


Scottish Building Society is mentioned in this post. 
 

 

 

Just got a knock back from them earlier today : (

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On 15/10/2020 at 12:44, AliG said:

Welcome, where are you building? I am in Colinton.

 

GSHP is surprising, I couldn't see how it worked due to the high cost of putting in the coils.

I'm in Balerno¬†ūüėÄ

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3 hours ago, Firsttimer said:

Hello Scotland. I'm outside Edinburgh in Balerno. Just got planning after ten months. The next hurdle is a mortgage - was hoping to do ICF, Zinc and Larch cladding. But having spoken to Buildstore they are coming back with just the Halifax. Who won't lend a sensible amount of money. Maybe it's based on being self employed rather than the rona... Any suggestions would be gratefully appreciated.

 

It's tough in Scotland, less lenders.

 

I had a knock back from the Scottish Building Society but got there in the end.

 

Buildstore came back to me with Newcastle building society, but this had a ridiculous amount of fees.

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5 hours ago, newhome said:


Quite a few people on here have used Ecology. 

I'd highly recommend. The SAP calc is minimal hassle,.just aim for over 85 and theoretically all else being OK they will accept you 

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Hello all. we are awaiting legal completion, so excuse lack of address and details for now. It is not superstition, but experience. Highland will do for now, and it is quite big.

I am juggling my own experience in commercial projects  with the more relevant experiences in your projects. 

Conversion of farm steading, not new, but will be airtight and well insulated.

 

question 1 space and water heating.

My thoughts are to use ground  or air source heating but also have oil or propane as security, and as best capital outlay value. Plus a wood burner.

I feel that most of you are going for AS with perhaps electric backup.

in commercial buildings i have specified and used AS many times, but never GS as the ground is heavy clay where we live.

AS is noisy though.

 

And solar panels?

 

I think underfloor is a given for a new floor, which we would have.

 

I'd love to hear your opinions.

 

question 2. rock wool or foam board in the walls and roof (see how I  am avoiding trade names)? I was tending towards foam to keep it skinny, but I like good quality rockwool, and see it on some project photos here.

 

thanks

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ASHP and WBS as secondary heat here.

 

The ASHP is noisy thing is a myth.  I would say the ASHP is no more noisy than the burner of an oil boiler, but the big difference is all that noise from the ASHP is outside.  Why is it people complain about a small noise from something outside but are happy to put something equally noisy (oil burner) inside their house?

 

Obviously putting the ASHP on your patio might not be the best plan, and nor would putting it on the boundary so as to annoy a neighbour.

 

Rockwool has a longer decrement delay, which basically means the time taken for heat to pass through a wall is longer.  The foam type tends to have a shorter decrement delay. You want the delay to be more than 12 hours so as the day warms up, the heat never has chance to get through to the inside before it is cooling down again.  For ease of handling I recommend the Knauff Earthwool type, far less nasty to handle that the old yellow glass wool type of stuff.

 

Re your steading?  Have any surveys been done?  While a steading conversion can work out well, I do know of one where they needed to lower the floor by 30cm to give room for 2 storeys, but then they started digging they found there were no foundations at all under the walls.  it ended up with a re submitted planning application and a knock down and rebuild new, just using the old stone for cladding.

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Interesting, thanks.

 

So the ASHP runs as standard, and slightly undersized, and the WBS is used when necessary for room heat 

Is that a wood-burner with back boiler, or a plant-room burner? logs/ chips/ pellets?

What about hot water?

 

I agree re noise, and it can be screened to some extent.  

 

I have been designing buildings for decades and had not heard of decrement. Reading to be done. Seems complicated, linking U value and thermal mass.

Perhaps more important  in hot countries, keeping heat out? 

I like rock / earth wool when it is the waterproof type as it fills voids tightly, whereas foam board is a bit approximate.

 

Survey only by my daughter and her husband so far. Lots of photos and videos for me, and they knew what I needed to see from a joint inspection of a similar building. 

I am a Chartered Civil Engineer, and have been contractor for 30 years. Also we have done up 4 places before, so know the pitfalls, or some of them. Will need to see it all close up, and soon.

 

Agreed re the floor and not digging. Would not want to undermine in the slightest. The floor is concrete, fairly modern and flat and clean. Therefore it will be left in place in lieu of hardcore, then dpm, ins and screed on top.

Plenty headroom, and we could always trade off an inch or so of insulation and put it elsewhere: but I think it is ok for 4 metric inches.

Will have to cut in locally for drains, and burrow under the walls..

 

I have read blogs where people have been told to break up the concrete and then put down stone. A lack of understanding or thought by the designer (?)  not the Building inspector's problem, and the poor owner does as told. Not with my money you don't. Money, complete lack of sustainable thought, and unnecessary risk to the building.

 

I was hoping to see more stone buildings in this hub, as there will be a lot of scope for not reinventing the wheel. For example, in one blog , I learnt to stick on bituthene to the bottom 1m of the wall, linked to the dpm...what a good idea, and probably standard.

 

It's great that you, and others, run this hub.

 

Oh one more thing. for a laser survey to produce a 3d drawing. In expensive Kent we pay about £600 to £800 but up your way it is over £2,000! Is  that just lack of competition.

We will get the tapes and level out.

 

Thanks again. don't feel you have to answer all the above!   Para 1 I'd like to know though.

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6 minutes ago, saveasteading said:

Interesting, thanks.

 

So the ASHP runs as standard, and slightly undersized, and the WBS is used when necessary for room heat 

Is that a wood-burner with back boiler, or a plant-room burner? logs/ chips/ pellets?

What about hot water?

 

Yes we have a 5kW ASHP roughly twice what the worst case heating load is.  It runs without issue.

 

The WBS is really an indulgence.  Partly because fire wood is so easy to get and free here.  It is used on those dull wet grey days when even with the house at it's usual 20 degrees you "feel cold" so it is nice to stoke it up for a few hours with free fuel and raise the whole house to 25 degrees and feel snug and warm.  It's also a backup form of heat should there be a power cut or something break down.  And useful to warm the house quickly if you have come home from holiday to a cold house (about the only time I would actually find a use for remote internet access to the heating controls so you could turn it on a day or 2 before your return)

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2 hours ago, saveasteading said:

I was hoping to see more stone buildings in this hub, as there will be a lot of scope for not reinventing the wheel. For example, in one blog , I learnt to stick on bituthene to the bottom 1m of the wall, linked to the dpm...what a good idea, and probably standard.

there are good reasons why you don,t see many stone buildings  on here 

firstly the walls are so thick and of no insulation value what ever - mine are 700mm thick -so you will end up in building a wood frame house inside it with a gap between it and the original walls --which then make room sizes much smaller --as you will be adding close to 200mm per outside wall --so room shrinks by 400mm +

50mm air gap +140/160mm wood framed walls  and allow it to vent at the wallhead to outside 

very few if any old stone houses have foundations -so they suck up damp from ground as they don,t have a DPC either  in the walls .

If old building it will be lime mortar so it has to breathe as its not water tight .

the reason most say remove floor is that you need a DPC under floor +150-3000mm of insulation+ 100-150mm of concrete to fit your UFH into

your UFH is trying to heat the whole of scotland  if you skimp on insulation in floor area 

Tanking the bottom of existing wall might work but moisture will still be rising from the lack of foundations and would need to have any exterior soil build up around the building moved away and a french drain to help stop the rising damp

 

 its for these reasons that so many old houses had wood panelling  up the walls --wainscoting  the walls --and old lathe and plaster started well of the floor

 

 these are some the reasons why any builder will tell you --if you have a choice --to flatten and start from scratch -as it will be cheaper and better --you can still clad in stone if you wish .

 get the fabric correct and heating it will be very easy with whatever system you choose.

 

 

 

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Excellent points both.

ProDave:   I am guessing that your domestic hot water is electric.

 

ScottishJohn: we are considering the 600 th stone walls to be an extravagant  weather-skin, much thicker than brick. 

Then we have a timber water and heat tight shell inside. the room widths become rather narrow but we are working on optimising that.

The steading unusually has 4 sides so the floor space is quite large still, and the roof truss bottom chords are a good metre above eaves so this helps. 

Your mentioning the constant dampness of the stone is interesting. I think it must be less damp then brickwork because of the density and large proportion of stone as compared to brick and mortar. But we still must keep it out, and I think a breather membrane is to be preferred to a complete barrier. 

Yes french drains will help, ( I think a rubble drain was built as standard along the walls, but that is well blocked by muck now.) A proper gutter and drain system, instead of being chucked on the ground will help most.

As a consultant or builder, yes I would tell any prospective client that it is cheaper to start again. As an owner, we will treasure the history, put in lots of time at no charge, and do the best we can. It is the unknown unknowns that are the biggest concern.

 

Re damp, much as I prefer rockwool to celotex, the latter is waterproof and an additional barrier to damp, and air.

 

I am comfortable with the theory, but there will be specifics for steadings that a) work well b) satisfy the inspector.

If only I could see other warrant applications it would be easy.

 

Both: do you know any clever way to Slap openings without the walls crumbling or, at least, being angled back excessively?

we will minimise this but will be at least 2 windows required.

I am thinking, do one side of an opening at a time and immediately rebuild the jamb in stone/block/brick. Perhaps use props and strongboys both inside and out. Then once the 2 sides are formed there is still a lintel to do, so do one out and one in, and never make a complete hole.   Someone has done this before though, maybe a better way. Saw cut?

 

Its great to have your advice. Tell me when you have had enough from me. 

I plan to do my bit for the website in answering other queries where I can add expertise. (Fire, drainage, sustainability without gimmicks). Seeing someone plan to spread intumescent paint as far as the tin would go concerned me yesterday, so I jumped in there.

 

 

 

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5 hours ago, saveasteading said:

Excellent points both.

ProDave:   I am guessing that your domestic hot water is electric.

 

DHW is heated by the Air Source Heat Pump in a Telford 300L ctlinder with the high capacity heat pump input coil.  Topped up using the immersion heater to use up surplus solar PV

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 the answer to the thick stones is to get them cropped down to 100mm --like a brick --then any brickie will work with them 

cost locally here is £40sqm to get my own granite cropped --less than half the price of new cladding stone -or if you hands on hire a cropper and do it yourself

 that way you can keep it looking like it did --and gain alot of space inside 

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22 hours ago, saveasteading said:

Re damp, much as I prefer rockwool to celotex, the latter is waterproof and an additional barrier to damp, and air.

I have full fill cavity with rockwall type insulation, it has a BBA certificate to say it does not wick damp, and I proved it, my west wall (brick) was soaked after a wet winter but when core drilling through the wall no damp had wicked into the insulation although the insides of the bricks were sodden. I have since treated the west wall with a damp treatment but have no worries about damp and this kind of insulation.

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On 22/04/2021 at 18:04, saveasteading said:

have been designing buildings for decades and had not heard of decrement

Not a real engineering term. Though, unlike 'thermal mass' you can put units to it.

Look up thermal inertia.

Or just divide heat capacity by conductivity. 

 

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On 22/04/2021 at 18:04, saveasteading said:

I have been designing buildings for decades and had not heard of decrement. Reading to be done.

 

Decent explanations here - https://www.greenspec.co.uk/building-design/decrement-delay/

 

Spreadsheet decrement delay calculator - https://www.concretecentre.com/Publications-Software/Design-tools-and-software/Dynamic-Thermal-Properties-Calculator-(1).aspx

I find it 'buggy' but it might just be my ancient Excel,

 

On 22/04/2021 at 18:04, saveasteading said:

Perhaps more important  in hot countries, keeping heat out? 

Or lightweight rooms-in-roof in summer

 

 

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Thanks all. It turns out I knew this instinctively, but it is very interesting to see the theory explained.

I have  a place in  Spain which stays cool indoors in the summer because of multiple  layers of tile and concrete, and some voids, but in winter  it is very slow to heat from indoors as the walls suck up the heat. It really needed both but there was no chance of convincing a Spanish builder. They do now sell insulation, but don't use  lot.

 

And I have built over 300 steel buildings, which have the 'caravan effect' whatever the u value (for about 2 weeks a year) It isn't a problem with high warehouse roofs but can be  for normal room heights. There is a solution which is several air changes overnight, to cool the structure. Woodfibre looks  an interesting additional possibility.

How many days of unremitting heat does Invernesshire get? I know it gets hot, but not usually for long.

 

The other aspect is of 50% more thickness with rockwool, and so another 100mm off the room widths. 

I am thinking that the higher roof will get lots of rockwool, 150? and some attic space, the walls and sceilings get 100 rockwool, and the floor is PIR, as much as suits ceiling height.

 

I will consider further, while drawing up sections, let you know the (provisional) decision, and welcome different opinions.

 

 

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Posted (edited)

I always find it interesting how PIR gets  rubbished all the time  

If it is that bad explain to me why when you build a cold store  you use PIR --not rock wool????-so temp stays stable and does not change 

 that surely proves that it is the best insulation --as frozen food people will not want to spend money on cooling more than they have to

 

 I maintain that it is air leaks in bad fitting of PIR that  is probably worst fault ,and as we now fit air tight vapour barriers to inside of house  even that problem will be very small

 

 the caravan problem -of pir bonded to roof sheets is simply that -direct heating of tin and direct contact of pir - and probably lack of a decent h/vac system inmost cheapo industrial units --so heat rises and sits there --you already have told us the solution --not rocket science  hot air rises and gathers if no draft or holes to allow it to escape

 the first big commercial units built in the 70-80,s had rock wool between the inner and outer skin , cos it was cheaper , and I can tell you from experience they were much worse than bonded type modern roof sheeting 

I believe the foil coating  on std PIR is to reflect the heat and that why purpose roofing PIR does not have it --cos it will   be in direct contact with roofing felt - no  air gap as in normal slate roof or air gap as it TF frame housing to outer skin

with MVHR any perceived advantages of rock wool will be negated as thats what it does --

for my part as I live in  rural scotland  --I just open a window --more gadgets means more problems and expense later on and  we don,t have the polluted air you city dwellers do .

 

Edited by scottishjohn

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8 hours ago, scottishjohn said:

always find it interesting how PIR gets  rubbished all the time  

If it is that bad explain to me why when you build a cold store  you use PIR --not rock wool????-so temp stays stable and does not change 

 that surely proves that it is the best insulation

I would like to see the thermal modelling and the costings before agreeing to your statement.

Building a house and building a large cold store are very different.

Just as an example if the difference, a cold store may have 1000 tonnes of fruit, taking up 80% of the volume in it. Fruit is 90% water, which has an extremely high SHC.

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21 minutes ago, SteamyTea said:

I would like to see the thermal modelling and the costings before agreeing to your statement.

Building a house and building a large cold store are very different.

Just as an example if the difference, a cold store may have 1000 tonnes of fruit, taking up 80% of the volume in it. Fruit is 90% water, which has an extremely high SHC.

I do not see how that would effect the insulation in any way 

 it is either stopping heat flow from inside to outside or vice versa or its not 

I have a large cold store next to my garage approx 30msquare by 20m high and on a _1c day i went out with my thermal temp gun 

outside of store on walls was same as ambient (-1c)

but because they skimped when building it --no insulation under the concrete floor -i watched them building it --I could measure -9c where I could get at the concrete foundations --an example of how things get skimped on  in commercial buildings . 

the walls were not allowing nay of the -30-40c to get to outside and they used 10" thick PIR panels to slot the thing together inside an exposed steel frame work 

 a digger damaged a panel; when tidying up outside after it was built  -all they did was cut out the damaged bit and stick in a new bit cur from a spare panel --hadn,t gone all the way through ,just a big gouge in outside

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4 minutes ago, scottishjohn said:

do not see how that would effect the insulation in any way 

 it is either stopping heat flow from inside to outside or vice versa or its not

Thermal transfer will take many paths, at different rates, it is all about minimising the overall energy usage. So without looking at the thermal model, it is impossible to say if one type of insulation is better than another.

 

One problem that wool insulation has is that air can travel through it. If this is not controlled properly, problems can happen.

Like most things, if done right  there is not a problem.

 

Out of interest, what colour is this cold store. They are usually white, or silvered.

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