How far from fence to retain sunlight into rooms? « Alternative Technology Assn Forums

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How far from fence to retain sunlight into rooms?

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Started 5 years ago by Annette
Latest reply from David

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Annette
Member

Hi

I am looking at building a new house ( finally after year's of trying to avoid it)! I want to retain northern sunlight into the house.

Would a full length window 2.5 metres away from a 1.95m or 2.5m fence allow sunlight into the room (there is a single story house on the other side of the fence).

The block runs East / West so I am just looking at designs that have the main living on the northern side.

My block is 15.24 metres wide. Many of the designs for 14 metre blocks would leave only 2.5 metres in front of least one of the living areas ( e.g. Simonds' Rio or Dakota.

Designs for 12.5 metre blocks would allow say 3-4 metres if I extend the garage to the boundary by a few metres e.g. Simonds' Palisade or Turin.

Posted Tuesday 12 Jan 2016 @ 8:58:30 pm from IP #
dave lawrence
Member

what is your latitude ?.
which side are you proposing to put the full height window ?
what will the difference in height be between the ground level and the sill height ?
these are some of the answers required to give a relatively accurate answer .
In an ideal situation you could post a basic site plan with building footprint and contours to avoid confusion. sketches tell more than words sometimes !

Posted Tuesday 12 Jan 2016 @ 10:18:01 pm from IP #
Catopsilia
Member

Details will depend on the latitude of the place where you are building, Annette.
Speaking generally, the bottom part of a full length window would be likely to be in the shadow of a house and a fence to the north.
May I ask, why do you want a full length window? What is it for?
Most modern houses have too much window space for energy saving.

Posted Tuesday 12 Jan 2016 @ 10:25:19 pm from IP #
Morbo
Member

The angle of the sun in the sky at noon can be easily calculated for the solstices and equinoxes as follows: Equinox = 90° — latitude. Summer solstice = Equinox + 23.5° Winter solstice = Equinox — 23.5°

Melbourne winter worst case 52 deg, so distance to fence (2.5m) timens tangens 52 is 3.2 m, thats how high the fence could be.
School finally paid off.

Bear in mind, in a few years there may be a double storey house in front of you.

Posted Wednesday 13 Jan 2016 @ 4:14:54 am from IP #
Annette
Member

dave lawrence said:
what is your latitude ?.
which side are you proposing to put the full height window ?
what will the difference in height be between the ground level and the sill height ?
these are some of the answers required to give a relatively accurate answer .
In an ideal situation you could post a basic site plan with building footprint and contours to avoid confusion. sketches tell more than words sometimes !

Not sure about latitude - in Melbourne.

Full height window ( I mean from the internal floor level or about 300mm from the floor) on north side.

Height from finished floor level would be either 0mm, or 300mm I think. However, I don't know how far from the ground as I don't know how thick the slab would be.

I have a site plan of the existing house; will see if I can post.

Posted Wednesday 13 Jan 2016 @ 4:19:53 am from IP #
Annette
Member

Morbo said:
The angle of the sun in the sky at noon can be easily calculated for the solstices and equinoxes as follows: Equinox = 90° — latitude. Summer solstice = Equinox + 23.5° Winter solstice = Equinox — 23.5°

Melbourne winter worst case 52 deg, so distance to fence (2.5m) timens tangens 52 is 3.2 m, thats how high the fence could be.
School finally paid off.

Bear in mind, in a few years there may be a double storey house in front of you.

Do you mean that at a distance of 2.5 metres from the fence, sun would still come In to the windows as long as the fence was under 3.2 metres?

Posted Wednesday 13 Jan 2016 @ 4:22:21 am from IP #
Annette
Member

Catopsilia said:
Details will depend on the latitude of the place where you are building, Annette.
Speaking generally, the bottom part of a full length window would be likely to be in the shadow of a house and a fence to the north.
May I ask, why do you want a full length window? What is it for?
Most modern houses have too much window space for energy saving.

My current house has full length (250mm from floor) windows and sun streams in all winter. However it is about five metres from the fence.

I am happy to have windows set off the floor, but thought that might block the sunlight

Posted Wednesday 13 Jan 2016 @ 4:38:47 am from IP #
dave lawrence
Member

my best advice without seeing the block would be to move the house psotiion as far from the north side fence as possible and be closer to the southern boundary. Elevating the floor height would also help. If ,as you say, there may one day be a two storey dwelling to your north then extra caution is advised.I agree with Catopsilia ..".Most modern houses have too much window space for energy saving."
Unless you have the budget for good quality double glazing then you would be well adivsed to think carefully about too much glazing that does not receive adequate solar access .

Posted Wednesday 13 Jan 2016 @ 4:40:09 am from IP #
Annette
Member

dave lawrence said:
my best advice without seeing the block would be to move the house psotiion as far from the north side fence as possible and be closer to the southern boundary. Elevating the floor height would also help. If ,as you say, there may one day be a two storey dwelling to your north then extra caution is advised.I agree with Catopsilia ..".Most modern houses have too much window space for energy saving."
Unless you have the budget for good quality double glazing then you would be well adivsed to think carefully about too much glazing that does not receive adequate solar access .

Thanks Dave.

Yes, I am planning to stay as close to the Southern boundary as possible (though cooling winds also come from that direction).

The current house is elevated on stumps by about 800mm, and I hadn't taken that into consideration.

I thought I would try check that the north facing glass actually has solar access.
The neighbours say they have no plans to build a double storey, but who knows.....

Posted Wednesday 13 Jan 2016 @ 4:50:22 am from IP #
Catopsilia
Member

About the "cooling southerly winds" (Half your luck!) Annette:
While solar access can be calculated exactly, wind access is more chancy. I doubt that the distance of the house from the south boundary makes much difference. The main thing would be to allow for large window or door openings in the south wall of the house, and easy routes for the air to pass through.

Posted Wednesday 13 Jan 2016 @ 5:16:08 am from IP #
Annette
Member

Thanks Catopsilia

Yes, doors slam throughout the house when I open the laundry door on the south side when the cool change comes through.

I do wonder whether the position of the house angled across the block ( narrower gap at south west side opening up to about five metres on the south east side helps with the breeze. (Also the house is only seven metres by ten metres!)

Great for breeze, terrible for a workable Reno!

Posted Wednesday 13 Jan 2016 @ 5:31:14 am from IP #
Catopsilia
Member

Annette, since I let cool air in every summer night, I have had to prevent doors from slamming if a breeze should come up. Most of my doors are now fitted with bronze door stops with rubber plungers. You lock and unlock them with your foot.

Posted Wednesday 13 Jan 2016 @ 7:05:30 am from IP #
dave lawrence
Member

without seeing plans/sketches impossible to say ,BUT I reckon the key may be in reconfiguring the roofline to get wintersun into the middle of the house. 1000 variables at play I know but thats a rough guess.

Posted Wednesday 13 Jan 2016 @ 8:19:35 am from IP #
Annette
Member

I agree and I have seen many beautiful designs in Sanctuary, etc that would work. Problem is the price tag compared to my earning capacity even for a small house.

Have looked at about 100 volume builder houses in brochures (Metricon, Porter Davis, Simonds etc) and not a single one with a clerestory roof. Even in the pricier models.

Found a couple with a slightly indented courtyard though and getting the design set out on my site plan tomorrow.

Posted Wednesday 13 Jan 2016 @ 8:31:00 am from IP #
Eco
Member

The sun angle at solar noon on 21 June in Melbourne is about 29 degrees from horizontal. (This is near midday - earlier and later than that the sun would be even shallower and longer shadows cast.) So with some basic trigonometry tan29 = 0.554. So at a distance of 2.5 metres away the height would be 2.5 * 0.554 = 1.39m. Add on your 0.8 metre stump height = 2.19m.So a 2.5 metre fence or adjacent house would block some mid winter light. Consider getting more distance away if possible or don't have your windows full depth. (This assumes flat land - a slope will add or subtract from the calc.)

I also note you are on stumps so unless you are using reverse brick veneer you may have lower thermal mass (lower than with a slab anyway).So you may not be able to take in as much solar energy as a higher mass house. Windows may need to be a bit smaller.

Posted Wednesday 13 Jan 2016 @ 9:48:15 am from IP #
Morbo
Member

yes. If you start a line at 52 deg from the ground, 2.5m from the starting point you would be 3.2 m up.
With your floor hight, depends, if you go pretty much level. Check, if you have flooding overlay.
If your window starts at 300mm above ground, the fence could be 3.2 + 0.3 = 3.5 m high.
If you are in Melbourne suburbia, there is chances, all of sudden there are 4 townhouses in front of your fence. In theory there are rules on overshading, but they are not worth the paper.

Posted Wednesday 13 Jan 2016 @ 9:53:27 am from IP #
Eco
Member

http://www.aprbuildingservices.com.au/Files_ESHM/ESHousingManualCh03.pdf

Morbo - I think 52 degrees is sun angle at equinox. Agree with you about the potential problems with North side development or trees on adjoining land.

Posted Wednesday 13 Jan 2016 @ 10:08:08 am from IP #
Annette
Member

Residential zone 3 so unlikely to have three storey town houses. However, could have a double story. So maybe alL the Your Home advice about an East Wast block being best is not correct any more in the suburbs?

Volume builders in Melbourne don't build on stumps, so it will be on a slab. My current house is on stumps, not the potential new build.

Posted Wednesday 13 Jan 2016 @ 11:15:42 am from IP #
Morbo
Member

yes, the 52 deg angle is worst case. Full height window will let lots of summer heat in. For winter, maybe make a sketch, how high the place north of you could be worst case. Then 52 deg down from there, this would be the lowest point of your window. 52 deg is still quite steep, you don't have to go back that far. Plus, does the house really have to be 10mdeep, if you have lots of width?
The orientation is still ok, as it will avoid lots of western sun in summer.

Posted Wednesday 13 Jan 2016 @ 11:08:25 pm from IP #
Eco
Member

For passive design wide blocks a lot better than narrow blocks - for both North South and East West blocks. However they are also more expensive when subdividing - more street frontage with more road and other services construction per block. Long and narrow are cheaper to construct - more $ for the developer. So we all know what is mainly provided.
For EW blocks if they are a bit narrow there needs to be regulation to control building heights on the adjoining blocks to the North to ensure solar access. Don't know if current regulation is adequate or not. But I doubt it.

Posted Wednesday 13 Jan 2016 @ 11:27:38 pm from IP #
Annette
Member

I'm in a well established suburb that was subdivided over 50 years ago, but I see what you mean about the designs for new developments.

I actually think a longer but narrow house is better for passive design as it lets more north facing rooms be built. Also sunlight makes me feel very happy!

I doubt there will be more regulation to control height to the north - there are already some provisions which generally mean a second storey has to be set back a certain amount - as well as overlooking regs.

For all the people who would be happy with stronger regs, a greater number would feel constrained and that the potential of their property was devalued.

Posted Wednesday 13 Jan 2016 @ 11:52:18 pm from IP #
Eco
Member

I am in the for regulation camp. They may feel constrained but they would also get the benefit of the regulation on their northern side - if they or their designer knew enough or cared enough to take advantage of it. Instead they just want to unthinkingly stick up as big a box as possible with a large air con servicing the whole house - and then wonder why their heating and cooling bills are so high.

Posted Thursday 14 Jan 2016 @ 12:54:06 am from IP #
Annette
Member

Yes, but it is a bit like termite protection. Should be mandatory everywhere except Tassie, but people object to being forced to install it.

Posted Thursday 14 Jan 2016 @ 1:18:50 am from IP #
Morbo
Member

next door the complete block is in 100 year flooding zone, but their floors are at ground level. I even had to consider flooding overlay foe a small deck, even though just one post is affected. So, regulations do not apply for everyone.
It depends which way your street is facine, east-west ot N/S. Your block is then perpendicular to that. So, thats really easy to do, there is a main grid, and the side streets should be N/S, not E/W like most cases. All this would not affect the amount of sealed surface. Guess it was more about north facing backyards.
If its a new house, check your plans for useless expensive detail (crazy roof, lots of corners.....), put that money into something more useful?
If there is an easement, they cannot build over it. Also there used to be some clearance around the house for firefighters. Guess all no longer applicable.

Posted Thursday 14 Jan 2016 @ 4:12:22 am from IP #
Annette
Member

I just got the siting diagram for a couple of possible homes ( i.e. shape of proposed house set on my block, to scale) and there does seem to be enough room in front of the central courtyard to allow solar acess around 4.7 to 5.1 metres depending on which house.

Currently that is more than enough room for solar access even with the house next door. Luckily, I'm not in a flood zone. However, I would prefer stumps, though a slab gives better access for all abilities...

Posted Thursday 14 Jan 2016 @ 5:48:32 am from IP #
Morbo
Member

stumps move up and down and a slab is cround connected, guess cooler in heatwaves.
Check the code on dapths for strip footings and check your soil type. I am not convinced that what happens in my area (clay soil, classified highly reactive) is up to snuff.
Maybe if you really simplify your house, a proper builder and some drafting office will be same price than some volume builder. Volume builders are all about cutting costs and you get a shiny benchtop, cause thats the ounly thing people notice.
Drafting office does not have to comply to council regulations, so cheap as well. To put it bluntly. Councils only really check drawings submitted by architects.

Posted Thursday 14 Jan 2016 @ 6:13:51 am from IP #
Annette
Member

I'll get a comparison quote done by a friend who is in a building company.

However, volume builders are much much cheaper than others because of their buying power and the cookie cutter approach. Also they make their money with the extras - fancy benchtops etc. all much more expensive than if you bought and had them installed outside of the building process.

For example I was quoted $17,000 for hydronic heating through a building company, but got a comparison quote for less than $10,000. Unfortunately, slabs are not as easy to retrofit this sort of stuff.

Looking at the Homeone Forum which features lots of volume builds, I am amazed at how many people don't seem to know the importance of orientation. Probably because they don't know how it will affect their quality of life in the house in the long run.

Your comment about drafting offices not having to comply with Council regulations is not correct Any one who is building has the choice to use Council to certify the building or get a private surveyor. The private surveyor is usually about double the cost but can process the building permit in a week or so, whereas Councils are so over worked they can take several weeks.

I have already had a soil test done because I had started down the path of renovating ( and spent a fair amount on design etc) but now think that it is probably going to be more trouble than it is worth.

Posted Thursday 14 Jan 2016 @ 6:32:30 am from IP #
axess
Member

Hi Annette,

Getting the soil test is a good start. Spending money on design is never a waste. At least you might refine what you don't want in a house that way!

We contacted a designer who wrote articles for Owner Builder magazine and asked if he ever did work in the city. He did, and he talked to us for a couple of hours during a visit eliciting our likes and dislikes. The first draft was exciting and innovative, including all the solar orientation stuff, double glazed windows, curved roofs, meandering passageway, disabled access and rammed earth load bearing construction we'd requested. We vetoed the composting toilet but basically went with the rest and it has worked really well.

We built as owner builders employing tradies who grew to love working on something really different from their usual fare of boring brick veneers. We had the occasional dodgy tradie but it was rare and could be worked around eventually.

We are planning a small addition at the rear and employed a local designer (located through the Building Designers Association of Victoria (BDAV)). We looked at another local design place also with the BDAV and went through the interview process (works both ways!) and decided against them because they were too expensive for our small albeit complicated job.

I went on to obtain my Builders Registration after this, using our build as my case study during the intensive preregistration interview process. I did this for other reasons related to my work as well.

My point is you are quite correct about the cookie cutter approach to volume home builders. Limited design solutions enable them to cover their target market and add value fairly easily for little market risk. They also suit developers and keep costs down by at times screwing their subbies. This is a market reality and they won't change unless forced to by market changes and/or increased regulation. Their primary customers will ask minimal questions about sustainability features and are reassured by the sales people pointing at the water tank, LED lights and being offered PV "at a great discount".

If you want a house that performs to the site's strengths and incorporates high performing insulation, breeze control and minimum electricity and gas use then I would look for a BADV member in your area as a start. Then get a quantity surveyor to cost the house build and tender out the work yourself. The designer should have some contacts within the industry to get you started.

Good luck.

Posted Thursday 14 Jan 2016 @ 9:39:46 am from IP #
Morbo
Member

lucky you people do not know about orientation and all that. Most blocks are orientated wrong, so if people knew, you would have more competition to buy a proper block.
Reg compliance, we have seen, what next door submitted. For instance, architect has to submit overshading analysis for several times a day, several seasons. next door had one and North was not right. Also magically our house was 6m shorter and the garage 6m longer, so the 3rd doggyhouse would only overshade the garage. Aircons needed to be submitted, but they were not and alas, we had 6 condensers facing our bedrooms. If an architect would submit, there would be more scrutiny. Mass builders and developers have everyone in their pocket.
Soiltest is worthwile, if your foundation is not right, you have all the fun like doors moving and cracks, gutters not level.....

We are doing renovation, the plasterer said, in volume house is no time to make proper joints. He only does renos. And so do our other trades. May cost more, but cutting corners will bite you.

Posted Thursday 14 Jan 2016 @ 9:41:47 am from IP #
Annette
Member

Thanks everyone.

Posted Thursday 14 Jan 2016 @ 10:34:17 am from IP #

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