heading in a better direction .. probably... it's just the speed (or lack of speed) at which we are heading in a more sustainable direction .
Passive House Design in Victoria, I need a bit of help please.
(52 posts) (11 voices)-
Posted Sunday 13 Apr 2014 @ 8:06:24 pm from IP #
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Greg C
MemberYes, but the idea of Reverse Brick Veneer came from a study CSIRO did in 1957. They built 1:20 scale house of all construction techniques. The RVB was way ahead of any other.
So we used to know how to build house but have forgotten the knowledge. Does this mean we are in the dark ages again.
Posted Monday 14 Apr 2014 @ 5:55:00 am from IP # -
I am also a firm believer in having the most massive of the thermal mass walls internal.
(generally as a spine wall separating living zones and sleeping zones ) coupled with clerestorey windows shining winter sun on them , and where desired having wood stoves next to them .In my experience done correctly they are perfect for solar passive designs.remember heat radiates out in all directions of the wall, so why not utilise that by having the entire wall inside. leave the outside walls as well insulated double stud frames. just a thoughtPosted Monday 14 Apr 2014 @ 7:43:52 am from IP # -
tom
MemberAssuming Passive House is meant to be PassiveHaus, then you will need triple glazed windows. PassiveHaus also requires R10 walls, which means your double stud wall will need the cavity filled with insulation rather than as an air gap. If you're on tight budget then your master bedroom is ridiculously large. Our's is 4.3x4.0m and is plenty big for a queen sized bed and a tallboy. Your 1200x1200 shower is too big. In fact if you are really trying to save money then I'd pull 400-500mm off the north part of the house. As for having bathrooms in the middle of the house, I would not worry. If this is a properly sealed PassiveHaus then you will need a ventilation system for air-flow which means you can have rooms without windows no problem (ignoring natural light of course). If you're on a slab, then that is sufficient thermal mass given you have good sized windows to the north. Trying to get the most amount of thermal mass as possible is not necessarily the best goal. Too much and it will suck the heat out of the air, and potentially overheat as well.
Just my 2c worth.
Posted Tuesday 15 Apr 2014 @ 3:09:18 am from IP # -
axess
MemberHi All,
Speaking of bathrooms-
I assume the idea of designing a passive house is to design a house for the long term which may include periods of infirmity or disability.
Car accidents, or even sporting or work accidents may neccessitate greater access to bathrooms particularly, and having a larger or more accessible shower or toilet becomes essential.
870mm wide doors are useful as are rooms that can be multi-purpose particularly with an accessible toilet on the same level as a bedroom.
Some wheelchair bound or less mobile people tend to need higher levels of background heat or cooling so the passive house principles are great for them providing they can still use the other living functions of the house as well. In this case having an effective bathroom from day one also means having to avoid often expensive and urgent modifications that may be forced upon them later.
An accessible shower of at least 900mm x 1200mm with a good quality washable shower curtain or single glass panel, and a toilet 450mm from a side wall and 810mm from the front of the pan to the rear wall, and nogged walls to take later safety rails if required are a worthwhile investment now. IMHO.Posted Tuesday 15 Apr 2014 @ 8:53:54 am from IP # -
FreddyBare
MemberHi Dave, I'm thinking I might have enough thermal mass with the slab and with the possibility of the wall behind the fire being brick, yes no?
Tom, I would love to have a 'PassivHaus' but I could never afford it with my budget, when I said 'Passive house design' I suppose I'm trying to run with some of the ethos of PassiveHaus design, but without the great expense. I'm guessing with correct orientation, window size, thermal mass, fairly airtight and plenty of insulation, I'll be a fair few step ahead of the 'masses' and have myself a comfortable and hopefully not an overly expensive house. I've actually taken 800mm off my north wall to shrink the house a bit and I'm playing around with moving the bathroom to the south wall, with not much luck.
Wow Axess, I hadn't thought of adding things like that to my design, but a lot of that would be quite simple with my design and not cost too much more (are 870 doors pricey, I know 720,820,920mm are pretty standard in Vic) Can I ask what the reason for the distance from the back wall the the edge of the bowl though?
Posted Tuesday 15 Apr 2014 @ 9:59:01 am from IP # -
axess
MemberFreddyBare,
Front of the pan to rear wall, and 450mm from side wall to pan centre is give enough room to transfer from a wheelchair to the toilet seat, particularly if rails are used as well. You have probably seen this layout in public toilet cubicles. Not strictly necessary in domestic situations but easy to achieve when designing from scratch. The common domestic measurement is usually about 650mm. Adequate circulation space in bathrooms and toilets is essential in my opinion if you wish to stay in a place long term (and also make is appeal to a broader market if you have to sell for some reason).
I do a lot of disabled access work and see everyday how easy it is for a house to become inaccessible. Therefore my own house is rammed earth with lots of passive solar design, solar hot water and a recently upgraded PV system. The accessible aspects were designed in from day one because of what I see every day.Posted Tuesday 15 Apr 2014 @ 10:16:00 am from IP # -
FreddyBare
MemberAxess,
Do you see some concerns with my plan, re ventilation and a future purchasers like if the design?Posted Tuesday 15 Apr 2014 @ 10:52:56 am from IP # -
axess
MemberHi FreddyBare,
I had a squiz at your drawings but couldn't read them.
There are many good designers in Melbourne and quite a few very good Green Builders who operate in places like the MBAV Green Builders. You could also try
http://www.bdav.org.au/10-Star-Challenge for some design tips.
Good design is worth its weight in gold.
Good luck with your house. BTW I was a fitter & machinist (gearcutter) in a previous life.
Posted Tuesday 15 Apr 2014 @ 11:12:00 am from IP # -
FreddyBare
MemberIf you download the drawing it is a lot easier to look at
And thanks for the links, I'm cash poor so hence self design, self build.
Plus I'm pretty fussy on workmanship, so I'd prefer to do most of it anyway
Being a Fitter myself (of types) I'm sure the fussiness runs through your veins too
Posted Tuesday 15 Apr 2014 @ 11:19:58 am from IP # -
Johnnojack
MemberFreddy are you going to shade the North windows? In late summer when it may be 40 in the shade sun can pour into those windows making it a very hot house?
An earlier suggestion to prune 1 metre off the north side means more sun on furniture. I deliberately made my current houses northern rooms deeper to avoid this.Posted Tuesday 15 Apr 2014 @ 12:55:39 pm from IP # -
tom
MemberFreddy, I like the design. I like how there are no east or west windows which is a big win on it's own. My comments about being too big were only related to saving money. Our showers are 1200x900 and we like them, but reality is 900x900 is fine, or even 800x800. Our last place had the shower over a small bath. It was 1600x650, but due to the angle of the bath was more like 1300x450. It was fine. As for room sizes, extra sized rooms don't cost that much, it's bigger kitchens, bigger bathroom, more wiring, ... that cost. Take a room 3x3. Make it 3.5x3.5 but with no extra power points, cupboards, etc. Extra cost is pretty minor.
As for my comments on thermal mass, it's just my view. Others here have similar opinion, but others here also think you can never have too much thermal mass. Our house is lightweight, lots of insulation, only thermal mass being the slab. So far it's fine. Air-con 3 times over summer. Heater not used since we moved in October. Only used air-con because we have too much east/west glazing and needed external blinds. You have no west glazing, 3 times as much north glazing. I think you'd be fine without extra mass.
Only opinion though ...
Posted Tuesday 15 Apr 2014 @ 9:59:33 pm from IP # -
FreddyBare
MemberI will have my eaves to shade my North Windows, I suppose going forward I will have to probably adapt some more dynamic methods, but that will be once I know what is happening and how to increase or decrease available light.
I've intentionally made the shower so that I can make it a double shower, but not as large as our last one that was 1800x900.
I'm guessing with the amount of North glazing, I'll be pretty right with the amount of thermal mass I have, I just wish my plan was 100% workable, not just me guessing.
Tom, so I suppose I should just leave that extra 800mm on my North wall as it probably wont add that much expense?
Posted Friday 18 Apr 2014 @ 6:09:06 am from IP # -
Greg C
MemberI have doodled around with my idea of all bedrooms and kitchen on the back wall. I think it will fit. Just take the Fasham plan as is for 1 bedroom, the bathroom, then the laundry/toilet. That is about 4970 long. Then stick a kitchen next, the kitchen in our place is 2800 x 3400 and it works. Then in your plan we have to fit an entry on the back wall so I think that comes next, lets be generous and make that 2800 wide. We have now consumed 10600 of the back wall. Next comes the other bedroom, and the mudroom next to it. You could push the mudroom into the ensuite of the master bedroom which is pretty big and could afford to give some up. Even allowing the mudroom to be 2810 wide, we are only up to 16700 or so. With the house 18600 long, we have no worries. I would fiddle around with the entry and kitchen, I think you could push a pantry into the entry space so you can have it narrower near the door and open up a bit as you walk in.
The other thing, have you thought where you will park vehicles. Without knowing the layout of the land, I think extending the roof on the southern side to form a large carport/undercover area would be a good idea. This would have the entry under cover and maybe make a space outside the house you can use when it is raining. There could be a 'lattice' wall just before the laundry door to separate the 'service' area of the house. Have you figured out where the clothesline will be, essential to do that so you can pick a place that will not be shaded by the house. The roof in our house is about 2800 high and our clothesline is 4300 away due south from the house. It does not get shaded at any time of the year.
As for shading, check out the house in the latest Renew. It has a powered blind across the north wall so you can adjust the amount of shading. Not a bad idea as there is hysteresis in the weather compared to the sun position. i.e. it is warmer after the summer solstice than it is a similar time from the winter solstice. I have found in Sydney at least it is a lot warmer in autumn and a moveable shade device could be handy.
Posted Friday 18 Apr 2014 @ 9:47:53 pm from IP # -
scott drew
MemberBeen away for a week so catching up on reading...
Couple of comments:
The HIA guy that thought thermal mass was a fad has obviously never spent any time in a house with thermal mass. I have a double brick internal wall in a room with a fireplace converted to a slow combustion heater. I run it hot for a few hours in the afternoon and the heat still can be felt coming out of the walls the next morning. That's the advantage of thermal mass.
If you're in the fire protection industry you may already know how long a masonry wall stays hot after a fire in the room.
Not sure of your age FreddyBare but worth considering Tom's comments on bathrooms and showers. I would suggest there is nothing wrong with a large shower (if you can afford it). I like (but will probably never achieve) the idea of a 'whole of life' house which is sustainable. By that I mean building a house once that will cater for your whole life. So it may be worth thinking about wide-ish doorways and large ish bathrooms to cater for when you get older. For example there's no point building a house in your 50's to enjoy but then having to move to a different place if age (and movement) catches up with you. So back to the point, a small shower may be cheaper now but a larger one may be more practical in the future if modifications are needed. Along with that, hob-less showers and no steps around the place can be advantages.
This forum is a wonderful place to bounce ideas around. Glad you are doing the bouncing prior to the build.
Posted Saturday 19 Apr 2014 @ 3:24:04 am from IP # -
tom
MemberI'm just playing devils advocate here. Less size means cheaper to build, and less area to heat/cool. But if you have kids, then less space might make it too cramped. More space usually 'feels' better as well. Some like big open spaces, some like small and cosy. I guess it depends on what you value you more - the extra space or some more cash in your hand/smaller loan. The question is how much extra cash, which only a builder can really answer you.
Posted Monday 21 Apr 2014 @ 10:21:37 pm from IP # -
FreddyBare
MemberHi Greg, I'm trying to understand your explanation of the modification of the Fasham house, but I'm not quite getting it sorry. I have modified my plan to allow for the Bathroom on the sth wall as well as made an airlock for the front entry. I don't have any real plans for covered car parking on the south at this stage, yes I'd like it and will need to work out something for the future, but I'm just trying to nut this plan out first
Hi Scott, I'm 39 so 'a whole of life house isn't a massive priority for me at this stage but If there isn't much added expense why shouldn't I just do it, maybe one day it would benefit me, a possible family member or a future owner.
Yes Tom, I'm having all of these tug of wars in my head constantly, bigger, smaller, cheaper, too small, too big, money, money, money. I already think my main bathroom is too small, I've update my plan quite a bit, I'll upload soon so that others can have a look and give their opinions on the newer direction.
Posted Tuesday 22 Apr 2014 @ 1:11:48 am from IP # -
FreddyBare
MemberI'm still having dilemmas with my wall insulation methods, I'm starting to go away from the double wall system, because if I insulate the outside wall, i feel I might still get some some convective currents or drafts in between the two walls, negating the purpose of the outside insulation. So I was thinking a single 90mm or 120mm wall with a 50mm foil face EPS (expanded Poly Styrene) board on the outside, all taped and sealed, then a batten on the outside of that to attach the colorbond sheet to. On the inside i would still have glass or poly batts,(even though I'd prefer rockwool, but I think it would cost too much? yes no?)
With putting Battens over the EPS sheet, would it be allowed to just screw the battens through the EPS sheet into the studs behind, or would there need to be a 'block' or something placed in the EPS so that it is an all timber 'joint'?
Posted Tuesday 22 Apr 2014 @ 1:25:22 am from IP # -
tom
MemberNever heard of colorbond screwed over the top of EPS. I would expect the battens would compress the foam too much and damaged it. If you search google there are a lot of panels available that have EPS (or XPS, PIR) properly bonded with aluminium or colorbond. Kingspan panels come to mind, and I think Bondor. Or one of 500 others if you're happy to import from China via Alibaba.
But a double stud wall, with cheap batts from Bunnings in both frames and the cavity shouldn't have any issues with convection. And would also be very well insulated. Do the outside stud wall with a closed cell spray foam and you have your water and vapour barrier too.
Posted Tuesday 22 Apr 2014 @ 10:05:22 pm from IP # -
Greg
MemberFB, your plan sounds fine. Have you worked out the insulation cost this way? ( don't forget the extra labour and time) Would it be any cheaper to go with 120 studs, wrap with reflective building wrap on the outside ( colour bond on that of course ) but spray foam the inside? When I used it , the price was about $18/m2. That way you would be air tight and unlike the batts, it won't sag. It could also be continuous into rafter space if you sprayed the roof as well, you'd have a complete continuous insulation layer.
Posted Tuesday 22 Apr 2014 @ 11:11:45 pm from IP # -
FreddyBare
MemberI spoke to a rep from Rmax yesterday, he told me i could screw the colorbond sheets directly through the EPS sheets into the studs, initially it thought this was strage, but then i remembered I worked on a woolworths project in Melbourne's south east and to create a thermal break from the roof to the metal purlins, they laid 90x90 EPS blocks on top of the purlins and the result was very rigid (bloody long screws though)
The reason I've decided this would be my best way, well I already have 84m2 of 50mm double foil faced EPS (maybe just more than half of what I need) and one 90mm frame would have to be cheaper that a 90mm and an additional 70mm frame. now I just have to work out what is the most effective insulative method to go with
plaster (or possibly MgO board) 90mm bulk insulation, in frame (possibly earthwool) 50mm foil faced EPS then the colorbond sheets?
I'm not sure what the R value of the 50mm foil faced EPS is but seems a range from R2 - R4 depending on where you look on the WWW
Posted Wednesday 23 Apr 2014 @ 2:21:29 am from IP #