Building 2 houses

[Sydney02]

Hi all,

 

my first post on what I've found to be a great forum for learning.

 

I am lucky enough to have been granted planning permission to build 2 detached houses in our back garden and are just at the stage of finalising the design with the architect. One is to live in and the other to sell. They are 2 storey brick and block construction, nothing too fancy but I am keen that we build well to create good homes that work well.

 

The construction will be managed by a builder and we will be hands off in a practical sense. One of my biggest concerns is the proximity of the site to a busy road. Having lived with fairly intrusive traffic noise for a number of years in our current house, I want to make sure we soundproof as well as possible. I think it will be quite interesting at the end of the build to see if any of the measures we take make a difference to comfort levels v our existing house.

 

we are also off the gas grid and that's thrown up another puzzle of the best way to supply heat and hot water. Do we just go for safe option of oil or a newer technology, particularly as 1 house will be for sale. It gets more puzzling again with the issue of summer cooling as throwing the windows open at night time isn't an option due to road noise.

 

anyway that's me. I'm a complete novice at this so will be happy to share my mistakes and cock ups as I go, maybe they'll be some successes to share too!

[Moonshine]

We have the same thing and are hopefully just about to get planning for two houses retaining the existing. 

 

One thing you will need to factor in is CIL as you will only be exempt on the house you are going to live in.

 

I can help you out with the noise issues as it's my job. The council may put on a planning condition for a noise assessment.

[ProDave]

The first thing I suggest is you look at the tax implications of building one to sell, particularly with regards to the self builders VAT reclaim scheme. (I am not the best person to answer that)

 

I would suggest you take a look at air source heat pumps for heating and DHW

[JFDIY]

Spread it out over a few years, get all the services in, build the first (which you don't want for yourselves), sell current house, move in, then build the second one,

 

this way you get to maximise your capital gains along the way, potentially avoid the CIL, have best cash flow and learn from the cock-ups to build yourself the better house.

 

Edited November 22, 2019 by JFDIY

[Sydney02]

Thanks Moonshine, I was reading up on the very stringent hoop jumping that CIL exemption required until recently, now changed so should be easier for your build, good luck for your application.

 

fortunately the council hasn't put any conditions on for noise but I want to try and make sure I get the materials and detailing right on the areas of weakness so the houses are comfortable. These areas seem to be sloping walls in the bedrooms (under the roof), the first floor ceiling and windows.

 

i talked to a really helpful soundproofing company today who suggested a fix for sloping walls in the bedroom to be a soundboard fixed to the joists with a further 30mm board attached, that board seemed to have layers of differing masses with some sound absorbing qualities too, which might also work on the first floor ceiling as well. I would be interested in your thoughts as I've found it's not an area my architect is particularly interested in.

 

i think I will probably end up with some optiphon glazing maybe in a timber window frame (no trickle vents! - acoustic wall vents instead) and looking closely at the gap sealing around each window frame.

 

One area I haven't really been able to find out much about is whether my choice of block makes much overall difference. The architect has  suggested a lightweight block but my limited knowledge on sound would suggest a denser block would add mass and be more effective, would be interested to hear your thoughts?

 

[ProDave]

Re the road noise.

 

I lived my childhood years on a busy road.  It just made me very intollerant to noise. I could never go back to living somewhere so noisy.

 

It clearly bothers you as well.  Yes you can make it better but that won't help you on a nice day when you would like a window open or want to go and sit in the garden.

 

So (apologies in advance) my off the wall suggestion is sell both plots and the existing house, and use the profit to find either a house or a plot in the quiet location that you really strive for?

[Moonshine]

10 hours ago, Sydney02 said:

fortunately the council hasn't put any conditions on for noise but I want to try and make sure I get the materials and detailing right on the areas of weakness so the houses are comfortable. These areas seem to be sloping walls in the bedrooms (under the roof), the first floor ceiling and windows.

 

i talked to a really helpful soundproofing company today who suggested a fix for sloping walls in the bedroom to be a soundboard fixed to the joists with a further 30mm board attached, that board seemed to have layers of differing masses with some sound absorbing qualities too, which might also work on the first floor ceiling as well. I would be interested in your thoughts as I've found it's not an area my architect is particularly interested in.

 

i think I will probably end up with some optiphon glazing maybe in a timber window frame (no trickle vents! - acoustic wall vents instead) and looking closely at the gap sealing around each window frame.

 

One area I haven't really been able to find out much about is whether my choice of block makes much overall difference. The architect has  suggested a lightweight block but my limited knowledge on sound would suggest a denser block would add mass and be more effective, would be interested to hear your thoughts?

 

 

No noise condition indicates to me it may not actually be that noisy, in the general scheme of things, however wanting to have good acoustical environment is important still.

 

A lot of the advice i am about to give is generic as i don't know the build, internal and plot layout, and importantly the noise levels on the site.

 

From your description, you have indicated that there are rooms in the roof, with noise coming in via the pitched roof. The construction of the existing pitched roof maybe very different from what the new constructions are going to be. The advice on reducing the noise in the existing spaces (if you really want to) is highly dependent on what the existing construction is, as if the house is from the 1930's it could well be just timber rafters with tiles on battens, with lathe and plaster underneath. This would need a fair amount of renovation to increase the acoustic performance.

 

For the new pitched roofs you could construct something like the attached metac pitched roof, which achieves a sound reduction (R_w) of 49 dB which is very good for a roof construction, but could be overkill for your plots depending on the noise levels. however this roof needs to be thicker than a standard pitched roof using PIR insulation, as the mineral wool is not as effective as PIR thermally for the same thickness.

 

In relation to the other aspects of the build, assuming standard block wall layout (e.g. 100mm block / min 100mm cavity / 100mm block), the noise intrusion isn't' going to be too affected by if you choose dense, lightweight or an internal skin of aerated blocks. Denser blocks will give better acoustic performance but all of these will give a sound reduction (R_w) of >50 dB, and its the glazing and ventilators which really need the focus as these are the acoustical weak areas.

 

Interesting that you have decided to go for the wall vents already rather than trickle vents, and agree you this give a better performance that trickle vents (max in frame trickle vent performance is ~D_n,e,w 45 dB). If you can locate the wall vents on the quieter facades this helps. A Greenwood MA301 (https://www.greenwood.co.uk/product/199/ma3051) is touted as the best performing wall vent with a  D_n,e,w of 55 dB again this could be overkill for your plots depending on the noise levels and how the plots layouts (e.g. rooms with windows facing away from the road will be a lot quieter).

 

Windows will be double glazed as standard, and having a laminated glass arrangement will help the acoustics, and the Optiphon will achieve that. In generally terms the higher the sound reduction (R_w) value the better the sound insulation will be, but i am unable to give advise on what spec to have as don't know the noise levels. What i would say is do a bit of a cost benefit analysis on how much higher sound reduction (R_w) glazing will cost you, and also maybe up spec just the bedroom windows (if that is where you have issues)

 

isover_metac_brochure_-_pitched_roof_solutions.pdf

[ProDave]

Other suggestions.  The outside of our house is clat in 100mm thick wood fibre board.  That seems very effective at reducing noise.  Everyone comments just how quiet it is inside (but then it's not very noisy outside)

 

I would go for a sealed house with no trickle ventilators at all and no direct fans. Instead install an MVHR (Mechanical Ventilation with Heat Recovery) and have the inlet and exhaust vents for that on the wall opposite the road.

[Onoff]

If you want quiet try 400mm timber I joists filled with Icynene like @PeterStarck's. Weird when you're used to a leaky, draughty old house. Felt like it was hermetically sealed but in a good way. Draught free, warm, ultra quiet but with fresh air.

Edited November 23, 2019 by Onoff

[Mr Punter]

As a minimum, get a valuation of the site as is, the GDV and a build cost estimate and put these on a spreadsheet.  Depending on where you are located, try build costs of between £1,500 and £2,000 and see how this impacts on profit / loss.  Don't forget to factor in plenty for professional fees and contingency.

 

Your main risks if you go ahead are Health and Safety / CDM, poor budgeting, escalating build costs, unexpected / unknown fees, contract management, quality management, achieving GDV estimates and achieving timely sales.

 

As you are a novice you may do better to sell the land, taking the uplift in value from your PP, or otherwise risk losing your shirt and your sanity.

[Moonshine]

37 minutes ago, Mr Punter said:

As you are a novice you may do better to sell the land, taking the uplift in value from your PP, or otherwise risk losing your shirt and your sanity.

 

Sage advice, especially as it's not your dream plot due to the noise.

Edited November 23, 2019 by Moonshine

[Sydney02]

Thanks for comments ProDave,

 

I have considered ASHP, particularly as 1of the houses will have solar panels (planning condition to provide 10% renewable energy). Another alternative I  thought instead maybe a domestic multisplit air con set up that might provide efficient warm air heating to the main rooms in the winter and also address any bedroom summer overheating if window cross ventilating isn’t possible as I should be generating some power at times when AC is required. Wall mounted electric rads and towel rails could fill in for rooms where warm air doesn’t reach in winter.
 

For hot water, Electric boiler could work for 2-3 baths per week, kitchen sink boiler tap and electric showers. I think I may have higher electric bills than just an ASHP but my capital outlay could be lower. The lack of a central system is probably a flaw and in practice might lack practicality but did seem to give heating and cooling options without breaking the bank.

 

i see you have ASHP, does it work well for you? Does it cope well with your direct hot water needs?

 

this would probably suit our needs so might be fine for the self build but the house for sale would probably need a more conservative approach, most people would probably be happy with an oil fired boiler.

 

I quite like your off the wall suggestion about selling everything and relocating to a peaceful desert island, would I have to tell the wife though! 
 

Although the noise does bother me it’s only really bedroom noise at night and early mornings, I can be out in the garden quite happily. Having a poke around in the loft at our current house, I can see that no attempts at acoustic insulation have been made, all the windows have trickle vents and some frames are badly sealed which makes me think that with some attention to design and materials and care around the construction i could make improvements over the current house.
 

JFDIY its a good suggestion,  the only worry seems to be that should HMRC look into it they would view me as trading rather than self building and probably hit me with a big income tax bill. I’ll be taking ProDave’s advice on talking to an accountant, I’ll share their view on the best strategy for this situation.

[Sydney02]

Thanks for that advice Moonshine, it’s really useful, the metac pitched roof is probably what I am looking to achieve. On the plans, the roof pitch cuts in at about a height of 1.6m in the bedrooms carrying on up to the ceiling at 2.4m, so I would lose a bit in the rooms from the deeper insulation but could live with that.

 

Going with a higher spec only on the bedroom windows makes sense. Do you think that timber frames make much of an acoustic difference over upvc? I had thought about external roller shutters in bedrooms partly to reduce summer overheating, do you think they make much of an acoustic difference?

 

The greenwood vent looks good.

 

 

 

 

[Sydney02]

We have been tempted to just sell the plots, there seems on paper to be a greater gain in building ourselves, particularly as we had to go through a lot to gain the permission in the first place.

 

but I think as someone with no experience I’m almost certainly underestimating the risks (financially and emotionally) and that does worry me. It’s really useful to get the perspective of people on this forum particularly as most of the people we’ve dealt with so far probably have a vested interest in us building rather than selling the land.
 

 

[Pocster]

You absolutely must build one , live in it . Build the other . Sell 1st and live in 2nd

Its not a quick turnaround but certainly don’t hand over CGT to the taxman !

Good on you for getting planning for 2 - maximise the return on your assets !!

[Moonshine]

3 hours ago, Sydney02 said:

I’ll share their view on the best strategy for this situation.

 

I would be interested in the outcome of that

[Moonshine]

2 hours ago, Sydney02 said:

Going with a higher spec only on the bedroom windows makes sense. Do you think that timber frames make much of an acoustic difference over upvc? I had thought about external roller shutters in bedrooms partly to reduce summer overheating, do you think they make much of an acoustic difference?

 

Yeah with a relatively small area of pitched roof, I don't think the extra thickness of the 'acoustic' roof would impinge on the space.

 

Wood frame is better as more mass there, assuming it's sealed correctly. But as long and the window and frame meet the required Rw then no real problem.

 

The shutter will add a bit acoustically but I would say just base it on the windows.

[Mr Punter]

2 hours ago, Sydney02 said:

there seems on paper to be a greater gain in building ourselves

If you post the figures or PM me I and others can have a look.  As a novice you may well have overlooked things.

 

2 hours ago, Sydney02 said:

particularly as we had to go through a lot to gain the permission in the first place.

 

Which will pale into insignificance compared to the construction and resales.

 

I think you would maximise your position with minimum risk if you were to sell the plots with the proviso that the work is completed within a fixed time.  You could use some of the cash to make any required improvements to your house to ready it for sale.  You could then sell your own house after the new houses are completed.  No tax payable on anything and no risk.

 

[Pocster]

1 hour ago, Mr Punter said:

If you post the figures or PM me I and others can have a look.  As a novice you may well have overlooked things.

 

 

Which will pale into insignificance compared to the construction and resales.

 

I think you would maximise your position with minimum risk if you were to sell the plots with the proviso that the work is completed within a fixed time.  You could use some of the cash to make any required improvements to your house to ready it for sale.  You could then sell your own house after the new houses are completed.  No tax payable on anything and no risk.

 

@Mr Punter is right . That’s the easiest way to maximise your gain with less hassle . But building each and living in each is the ultimate gain ?.

When I got planning I could of sold the entire plot with planning AND my house as one thing - no CGT ?.

But ; that was too easy . Better to split the plot . Sell my residential so no CGT . Buy something else to live in . Back at plot build house with of course ultimately moving into that . This kind of route isn’t for the faint hearted. As mentioned no matter what it took you to get here ( my planning permission took 5 years ) that ‘tax efficient, maximum return’ path becomes your life and you must be dedicated to the cause. The destination IS the journey  .???

Edited November 23, 2019 by pocster

[Pocster]

1 hour ago, Mr Punter said:

If you post the figures or PM me I and others can have a look.  As a novice you may well have overlooked things.

 

 

Which will pale into insignificance compared to the construction and resales.

 

I think you would maximise your position with minimum risk if you were to sell the plots with the proviso that the work is completed within a fixed time.  You could use some of the cash to make any required improvements to your house to ready it for sale.  You could then sell your own house after the new houses are completed.  No tax payable on anything and no risk.

 

Tax would be due on sale of plots ?!

[Mr Punter]

33 minutes ago, pocster said:

Tax would be due on sale of plots ?!

 

No. As long as the plots were part of the garden and sold off before the house, no tax payable.

[Pocster]

1 minute ago, Mr Punter said:

 

No. As long as the plots were part of the garden and sold off before the house, no tax payable.

Why is that ? I must have missed this tax break ...

Plots sold not main residence; surely income tax ???!?! ?

[Mr Punter]

4 minutes ago, pocster said:

Why is that ? I must have missed this tax break ...

Plots sold not main residence; surely income tax ???!?! ?

 

Nope. You can sell off plots in your garden without tax.  If you decided to build them you would probably be liable.

 

https://www.thisismoney.co.uk/money/experts/article-3420863/We-thinking-building-house-garden-pay-CGT-sold-it.html

[Pocster]

3 minutes ago, Mr Punter said:

 

Nope. You can sell off plots in your garden without tax.  If you decided to build them you would probably be liable.

 

https://www.thisismoney.co.uk/money/experts/article-3420863/We-thinking-building-house-garden-pay-CGT-sold-it.html

Ah I see !

?