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Our Design Drivers

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TerryE

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We've live in a 300 year-old farmhouse with lots of beams, wobbly walls and character -- and the odd draught. It's a large family house and, after 30 years living it, we feel that it is now time for a change. We aren't interested in a Grand Design; we want a modest design that is a good balance of function, of being practical and cost-effectiveness. Given this, our main drivers in selecting our design were:

  • Comfort and space. We want a smaller, cosy house with minimal running costs, low maintenance, and energy-efficient; with ample room for ourselves and a bedsit-style bedroom for a son who lives with us; with enough space to accommodate our two other children and their partners when they visit. We estimate we need an internal floorspace of roughly 200m² to achieve this.
  • Constraints on external footprint. Our plot is 14.5m wide, and our house is aligned across the plot because of the overall placement considerations. Minimum clearances to the left and right give us an external length of 11.5m. The LPA also requires that the overall style of the house fits in with the street scene, so must be faced with local stone and have real slate roof. It can have a maximum depth of 6.5m (1m less than we initially planned), though the planner also suggest we could have a rear gable, but again plot constraints (minimum rear separations) limit this to 2m. There are also constraints on the ridge height.

I know that we all bitch about LPAs, but in our case our planner is a nice guy and has been very helpful. Yes he has laid down restrictions on how we can use the site, but to be perfectly honest on reflection we agree on nearly all that he's suggested, and the rest was so marginal that it was easier just to go along with him. Our build has to be pleasing to the eye for ourselves and our neighbours; it has to fit in well. For example, we didn't like the idea of restricting the depth and adding the gable, but we found that this works really well when we planned it out and the house is more interesting to look at than a boring Monopoly house shape.  We have really pushed the plot to it's sensible limits in terms of the house footprint and envelope, and now we have fill that envelop to meet our needs.

  • External wall thickness. We have to balance a desire for high thermal performance and the impact of a deep wall cross section on the internal living space. When you are working outside-in you realise just how much of the slab footprint is taken up by the external walls: at a U-value of 0.15, the walls already account for nearly 20%. Usable living space has a value to us, so it's just not cost-effective to thicken the walls to drop the U-value further. We also have to go for a timber-framed build as we can't achieve this scale of U-value and have a cut stone skin any other way. The stone skin is a nominal 10cm deep but can be 25% deeper and stone needs backing or a controlled stand-off; we are using SureCav to mitigate the width impact of the stone skin, but a safe overall budget for this is still 17.5cm. A high-spec frame can achieve 0.15 with an overall wall depth of 40cm (though we may still have to go up to 45cm when we finalise the profile).
  • Use of loft space. We aren't going to achieve our target living space on two floors, so we will incorporate the loft space within the liveable environment. However, ridge-height considerations mean that we will have to limit our roof pitch to 45° and we will have ceiling heights less than we would have preferred (2.4m on ground floor and 2.3 on first). Even so, the loft pitch profile will still be tight, so we can't class this loft as full living space; however, it will still prove very useful floor space for two main functions: (a) this give us a good space for a MVHR / equipment / storage room; plus (b) an occasional-use / guest bedroom.
  • General layout. Our thinking is to keep the overall layout simple. The window-less gable constraint gives the house an internally feeling very similar to that of a double fronted terraced layout. We will have entrance hall and utility block in the centre of the house with the living room and kitchen/dinning area straddling this on the ground floor; bedrooms straddling it on the first. The bulk of the services are contained within this utility block. We want a fairly clean modern styling internally, and our main extravagance is that the hall space will be fairly large with the centre void carrying up into the roof space and floating staircases to the 1st and loft floors. Apart from the visual impact and sense of space, this also has a very pragmatic benefit of making it a lot easier to get bulky furniture and equipment onto the upper floors.

    Aligning all of the toilets, bathrooms, utility services on all three floors into a single block significantly simplifies pipe runs, etc. The only "outriders" are the hot and cold feed to the kitchen.  Another design decision was to make the internal fore-and-aft walls which divide the central hall/utility block from the rest of the living space aligned on all floors and load bearing. This eliminates the need for internal structural steel, and (since the maximum floor spans are now ~3.5m) reduces the depth of the inter-floor voids and giving more volume to living space.
     
  • Thermal design. This is very important to us. We are aiming for an overall zero-carbon design, albeit it with some careful payback constraints. This bullet merits it own post which I will do next.


So the final layout will look something like this.

TerryE%20Floorplan.jpg

Note that we've since decided to abandon the fireplace in the living room (though we'll leave the flue capped and in place to help buyer-proof the build), and the 1st floor void will be carried into the loft.

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Original comments:

 

ProDave 07 Sep 2014 12:29 PM

That looks a nice efficient layout. About the only thing I would change, is try and get a window in the rear gable end of bedroom 4 in the loft.
 

TerryE 07 Sep 2014 04:22 PM

I know; we liked like this idea as well, but our TA strongly recommended against because of possible overlooking objections. As it then turned out, the two material objections from neighbours were two that will be able to see the upper storey of the new house at the bottom of their gardens. Both objected to the roof lights, but these don't count as overlooking. A gable end window would have been another situation entirely.
 

The window in bedroom 1 can you move it over slightly or increase its size to let more light into the room. Every other room has a lot of light getting in except it. The staircase will look really nice.

TerryE 07 Sep 2014 07:26 PM
Declan, it's funny you should mention that, but Jan and I were sitting outside with a glass of wine early discussing Dave's comment and she said exactly the same ;)

declan52 07 Sep 2014 07:39 PM
Great minds!! If it was slightly wider it would look better on your elevation in that it will be a closer match to the doors below. I increased both of my gable windows by 200mm but maybe the lpa won't allow you to increase their size.

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I thought it mandatory that the downstairs wc door had to open into the hall or be a pocket door.

Might be sensible to plumb for a future wc & basin to attic.

Corner of Front door could open into someone descending stairs; hingeing door on other side would lessen impact.

I would personally reverse dining area with kitchen, it would also improve plumbing design. From a selling prospect some people could then expand kitchen into utility, not everyone likes a separate utility and may prefer a larger kitchen.

Very sensible design.

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I was supprised when our architect showed the cloakroom door opening outwards into the hall but he said it was building regs for disabled people ( but most people changed it around after sign off).

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I think the WC door issue is a little more complicated.


 

The WC has to be "accessible" and that means a certain amount of "activity space" in front of the pan, and nothing is allowed to intrude into that activity space (except a basin may partly overhang that space) and the door must not swing over the activity space. So unless you have a very large WC, the door would swing over the activity space, hence solving it by hinging outwards.

 

Our downstairs WC is unusually combined with the utility room, and the door into it will be a long way from the pan, and will open into the room. building control have confirmed this is okay as it will not interfere with the activity space.  They have also agreed that the door through from the utility / wc into the garage, would not normally be used by anyone in a wheelchair (due to the mandatory step between the house and the garage) so it does not matter if THAT door swings over the activity space, so that too can open inwards if we wish.

 

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I thought the most important reason for an outward opening door for a putatively disabled suitable loo was so that rescue was possible if someone inside collapsed against it.

 

The same applies to showers if we are being sensible.

 

Edited by Ferdinand
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23 minutes ago, Ferdinand said:

I thought the most important reason for an outward opening door for a putatively disabled suitable loo was so that rescue was possible if someone inside collapsed against it.

 

 

Thats what my architect told me.

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