Wow !..........so much to learn and so little time !

[Canoehq]

Here is my project going up just south of Newmarket.  Just under 3000sq ft and is an old hay barn being converted to our new house !  In about 0.7 of an acre.

Never done anything like a self build before, but hugely excited and hugely nervous in equal measure !

 

Yes, lots of glass and all south facing.  I guess I'm going to need some serious help from the collective gurus on here please, but I promise I won't become a pest !

 

Thanks all.

 

 

[Onoff]

Welcome. Some solar gain there! Going to need some shading/ cooling. Sage Glass if deep pockets maybe?

[SteamyTea]

Welcome.

With that much glasing I think you are going to need air conditioning.

Have you had all the thermal calculations done yet?

[Jeremy Harris]

Welcome.

 

As above, you're going to need to do a massive amount of work to mitigate overheating.  Stopping heat getting in is far, far easier than trying to get rid of it once it's in, so I'd suggest  making sure that the arrangement of brise soliels you have will be effective for all sun angles, consider using solar reflective glass, or perhaps Sage glass, and look to see if you can fit external blinds or shutters.  The latter can be very effective, more effective than probably any other solar gain reduction method.  There are lots of threads here on dealing with overheating through glazing, but I don't think we've yet seen a house with that much glass, so your challenges may well be significantly greater.

 

Not sure what you're considering as a heat source, but a heat pump would seem a good candidate, as it could be run in reverse for most of the year to remove heat from the house.  Floor cooling using UFH pipes works well, but with the amount of solar gain you're going to get I would consider fitting lots of fan coil units run from chilled water from the heat pump as well.  Both these systems could also provide winter heating.

 

Out of interest, how have you managed to meet the requirements of Part L1a with that much glazing?

[Canoehq]

Is/was being built under a Class Q Prior Approval conversion planning application, so the entire build needs to stay within the footprint of the original barn.  I'm not even allowed to remove the original old steel stanchions etc. and have to design around them.  Planning permission is for a conversion, so It seems if I take down the old building, it becomes a 'new build' which isn't allowed !!

 

Yes, the glass is a worry and no, not deep pockets, so cheaper glass with solar film or external shutters I guess.  Whatever stops the heat getting in, unless forumites have some better ideas before the first spade goes into the ground, as still time to replan !

 

Here's what it look like now;

 

[Canoehq]

11 minutes ago, JSHarris said:

Out of interest, how have you managed to meet the requirements of Part L1a with that much glazing?

Thank you so much for such useful help this early on, really kind.

 

Re your question, there are no other windows in the barn apart from the ones you see.  Actually, tell a lie, there are bi-folds on the kitchen gable end.

I'm hoping there are technical people out there who can advise appropriately, but generally find where there's a will.................  !

 

It's about 150 sq m of glass in all I think.

 

And yes, ASHP / UFH is in the plan.  Hadn't thought about running it in reverse !

Edited September 22, 2019 by Canoehq

[MikeSharp01]

Welcome to THE forum for self builders, be a pest we all are in our way but its a very collegiate pestilence and if you were building a tropical hot house you could do worse than start from where you are but it seems you have some good ideas and you know what / where the challenges are.  

[Jeremy Harris]

16 minutes ago, Canoehq said:

 

Yes, the glass is a worry and no, not deep pockets, so cheaper glass with solar film or external shutters I guess.  Whatever stops the heat getting in, unless forumites have some better ideas before the first spade goes into the ground, as still time to replan !

 

 

I had to fit solar film when we found that solar gain was too high, as have one or two others here.  It works, but it's not as effective as solar reflective glass, you can tell there's film on the glass and it was more expensive overall than if we'd have fitted solar reflective glass in the first place. 

 

External blinds or shutters can be very neat and effective.  Worth designing in, as then they can seem invisible when retracted.  One or two here have then fitted, and have described how they look and work in other threads, so might be worth seeking those out.  Retrofitting external blinds is possible, but never looks quite as neat.

 

12 minutes ago, Canoehq said:

Thank you so much for such useful help this early on, really kind.

 

Re your question, there are no other windows in the barn apart from the ones you see.  Actually, tell a lie, there are bi-folds on the kitchen gable end.

I'm hoping there are technical people out there who can advise appropriately, but generally find where there's a will.................  !

 

 

If not done yet, then I think that an early run through SAP would be a great benefit, to see how far off you are from meeting the regs.  Having bifolds will make things worse thermally as they will inevitably end up with poor sealing after a while, reducing airtightness and increasing heat loss.  Have you considered something that will be significantly better thermally, like lift and slide doors?  You can still get large openings, but without all the intrinsic issues that beset bifolds.

 

 

[ProDave]

Hi and welcome.

 

You certainly have some challenges there.  As it's certain you are going to need active cooling, I suggest you install solar PV to help power that in the summer. Probably ground mounted.

 

Please don't take this comment the wrong way, but I think this build illustrates just how plain stupid our planning system has become.  You have got permission to convert that open Dutch barn into a house, but let's be honest for a minute, that building is the very last building I would consider a candidate for conversion. Nothing about it lends itself to conversion.  You are in effect building a new house and sitting it under the tin roof of an old barn so it is counted as a "conversion".

 

And this is where I think the planning law is just plain bonkers.  It would be far far better if you were allowed to knock that down and build a proper house from scratch, of no greater size than the old barn.  You would end up with a better house technically, and (please don't take offence) a better looking house.

 

Having said all that and hoping I have not upset you, you certainly have some interesting challenges ahead.

[Nick1c]

Floor to ceiling glass is loved by architects & is great for drama. It is also expensive, thermally inefficient, increases overheating potential and may well reduce the useful space in the room. If you have jaw-dropping views think about how best to frame them, from a practical point of view  you could probably halve that amount of glass & still have more than enough light. It seems particularly extravagant in bedrooms. 

Having said all this our house is pretty highly glazed......

[Canoehq]

31 minutes ago, MikeSharp01 said:

Welcome to THE forum for self builders, be a pest we all are in our way but its a very collegiate pestilence and if you were building a tropical hot house you could do worse than start from where you are but it seems you have some good ideas and you know what / where the challenges are.  

 Again, thank you.

 

I've been lurking in the background reading the various threads on here for some months.  It really is a brilliant place and a credit to the very kind people who take their own time to post up to help others.

 

In many ways, as my wife and I are as amateur home builders as you could ever imagine, I would almost like this to become a showpiece project for the Forum itself !  

Whilst we have some ideas that we would like to design into the house, none of them are as yet, set in stone, so we are more than happy to be persuaded/advised by better ideas the forum can come up with (within our modest budget !). 

 

Yes, I really would like this to become the house the forum built !

Edited September 22, 2019 by Canoehq

[Canoehq]

LOL !

All positives so far then !

 

........and no, the very last thing I will ever be is upset.  Just grateful for the help !

 

But we have a few months yet getting things and ideas straight before we need to start building, so the more ideas that can be thrown at me, the merrier ! 

Edited September 22, 2019 by Canoehq

[Dreadnaught]

To add to the avalanche of (well-meaning) concerns about overheating, I read somewhere (was it the Passive House handbook?) that the lower part of a floor-to-ceiling window contributes very little in terms of view-out or light-levels inside… but adds greatly in terms of heat ingress and overheating in general.   

 

For my forthcoming build I decided that my large windows would be from waist-height upwards. The design aesthetic still works (I think) with contrasting exterior cladding for the section beneath the windows that would have been glass if I had stuck with floor--to-ceiling glazing.

 

My other concerns about floor-to-ceiling glazing is that: (i) it puts on-show the clutter of daily living; and (ii) prohibits furniture under the window.

Edited September 22, 2019 by Dreadnaught

[NSS]

11 minutes ago, Canoehq said:

Yes, I really would like this to become the house the forum built !

Don't do it! If there's one sure way to ensure it ends up looking like a dog's breakfast, it's to design by committee ?

[ragg987]

Welcome and best of luck with this venture.

 

Apart from concerns about over-heating when sunny, you should also consider heat losses in winter.

 

On a cold grey day, or at night, all that glazing will dump heat out, though if slightly sunny the solar gain would be a great boost. You might want to consider how you can use this to your advantage - e.g. having mass in the building envelope that will capture heat in the day and emit it in the evening. Could be something as simple as thick concrete or brick elements.

 

How well insulated are the other elements of the fabric - roof, walls, floor?

[Canoehq]

1 minute ago, ragg987 said:

How well insulated are the other elements of the fabric - roof, walls, floor?

 

Don't know yet, designs still being finalised, so up for any advice whatsoever that will let me short cut months of mistakes or the dreaded "I wish I'd thought of that earlier" afterwards ! 

[Jeremy Harris]

2 minutes ago, NSS said:

Don't do it! If there's one sure way to ensure it ends up looking like a dog's breakfast, it's to design by committee ?

 

^^^^ Definitely this! 

 

Couldn't agree more.  We can all give advice based on our own experience and knowledge, but your house must be your own, and meet your needs first and foremost.  Our views will be coloured by what we each prefer, and where we are each prepared to make compromises, and that may well be a million miles away from what you're seeking.  We're also scattered all over the UK and NI, living in a fair range of different weather patterns, from members up in the Northern Isles and Hebrides who battle with high winds and rain, to those of us like me, down in the South and living at the bottom of a sheltered and very warm valley.  All these things will colour the advice we give, even if we try not to let it.

[Canoehq]

1 minute ago, JSHarris said:

 

^^^^ Definitely this! 

 

Couldn't agree more.  We can all give advice based on our own experience and knowledge, but your house must be your own, and meet your needs first and foremost.  Our views will be coloured by what we each prefer, and where we are each prepared to make compromises, and that may well be a million miles away from what you're seeking.  We're also scattered all over the UK and NI, living in a fair range of different weather patterns, from members up in the Northern Isles and Hebrides who battle with high winds and rain, to those of us like me, down in the South and living at the bottom of a sheltered and very warm valley.  All these things will colour the advice we give, even if we try not to let it.

 

Good straight advice.  Thanks, I like that !

[ragg987]

1 minute ago, Canoehq said:

Don't know yet, designs still being finalised

I suggest you factor this in at an early stage as a design principle, it will be harder and more expensive to retro-fit.

 

Example the pasiv standard calls for high insulation, minimised thermal bridges, controlled solar gain, well sealed fabric and positive ventilation approach. None of this will happen by accident, if your intention is to aim for something similar get it agreed early as it has impacts all the way through the design. @JSHarris has provided one example - bi-folds.

[Nickfromwales]

Hi @Canoehq and welcome to the forum. 

Are you allowed to remove the existing slab / floor and reinstate with new? 

Bottom line is; can you add insulation to the slab now or will you have to beef that up retrospectively?

[Canoehq]

Just now, Nickfromwales said:

Hi @Canoehq and welcome to the forum. 

Are you allowed to remove the existing slab / floor and reinstate with new? 

Bottom line is; can you add insulation to the slab now or will you have to beef that up retrospectively?

There is no slab.  Just a dirt floor with the current stanchions on shallow concrete pads.

[ProDave]

Can I ask why did the architect make everything floor to ceiling glass?

 

Was it because that is an open side at the moment, and he thought near 100% glass would make it look more open like it was originally?  If so I would say that is misguided.  You are changing the use and function of the building, so I would not have any concerns whatsoever about making that a solid wall with an appropriate amount of glazing to give enough light and views while controlling heat loss and gain.

 

If it was the planners that insisted on all that glass then my despair of the planning system just gets worse.

[Jeremy Harris]

6 minutes ago, Canoehq said:

There is no slab.  Just a dirt floor with the current stanchions on shallow concrete pads.

 

 

That's an advantage, as you should be able to lay a reasonably well insulated slab and then look at ways to deal with the insulation of the stanchions, if they are going to be within, or partially within, the thermal envelope.

 

Are you looking at building what amounts to a new house inside the existing barn, in effect?  Would seem a reasonably good option, as that way you're not constrained by the stanchion load bearing capacity.

[Canoehq]

3 minutes ago, ProDave said:

Can I ask why did the architect make everything floor to ceiling glass?

Yes, architect and planners didn't object !  No doubt he was after a design award or something but with little thought as to how someone would live there afterwards !

 

3 minutes ago, JSHarris said:

 

 

That's an advantage, as you should be able to lay a reasonably well insulated slab and then look at ways to deal with the insulation of the stanchions, if they are going to be within, or partially within, the thermal envelope.

 

Are you looking at building what amounts to a new house inside the existing barn, in effect?  Would seem a reasonably good option, as that way you're not constrained by the stanchion load bearing capacity.

 Yes, an entirely new steel frame being built over the same footprint, with new slab and/or deeper pads as needed.  The old stanchions need to be retained apparently, but will be bolted to the new frame and hidden.  They will not be load bearing. 

[Thedreamer]

@Canoehqare you up to speed on VAT rules for barn conversions?