Multi Unit Dwelling

Questions, comments and suggestions about the Design Navigator H1 Compliance calculator

Multi Unit Dwelling

Postby S M Piner » Fri Jun 26, 2015 9:54 am

Hi Albrecht

I have a small apartment block to document and am wondering if Design Navigator Compliance calculator can be used for determining H1 compliance for this, and if so how it can be applied to this type of building.
The building consists of 5 floors containing a ground floor shared garage space and lobby / stair/ lift well with apartment 1 in the first 2 floors and apartment 2 on the top two floors. Above this is a Roof Terrace with a small lobby / stair / lift well space. Construction consists of a reinforced concrete beam and column structure with precast concrete flat slab & in situ con slab floors. The side walls to the rectangular building are pre cast conc boundary walls to neighbouring similar buildings ( it's part of a major development) and the front & rear walls are conc colums / beams with infill of double glazed aluminium joinery. There is only 1 external 'wall' as such that does not fall into either of the above categories ( apart from the roof terrace lobby).

Any advise on how to treat this building would be greatly appreciated.
S M Piner
 
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Re: Multi Unit Dwelling

Postby Albrecht Stoecklein » Fri Jun 26, 2015 11:21 am

Good question.

The simple answer is yes, the DesNav calculator can be used for all "housing" irrespective of size.

In your case you would treat the whole appartment block as one building, i.e. ignore all midfloors and inter-tenancy walls. The garage level would usually be left out of the calculations, i.e. you would insulate the floor over the garage. It is usually easier to include the staircase/liftwell in the calculation but because it is un-conditioned you also have a choice.

The glazed walls and the external walls are treated as normal.

The joint wall should be treated as an external wall, as well. The reason is that someone could decide at some stage to pull down that neighbouring building, and then your appartments would be left without wall insulation if you relied on the presence of that other building for insulation.

If you really can't insulate that wall you could try to argue that it is a joint wall and that there are no net heat losses. You could use an approach similar to an addition to an exisiting building. That means that for calculation purposes you would assume that the joint wall is insulated to the R-value target in the Schedule Method (R-1.9 in Zones 1 and 2 and R-2.0 in Zone 3). There is a bit of explanation about additions and alterations on the right panel on the H1 calculator log-in page https://www.designnavigator.co.nz/DNLogin.php. The difference is that in your case you apply the logic to the joint wall rather than including the neighbouring appartments in your H1 calculation and apply it to the external walls of the neighbouring appartments.

So in summary, insulating the wall would be easiest. In my opinion the "additions and alterations" approach would also be reasonable in practice, but it depends on how the BCA sees it.

I hope that helps.

Sunny regards

Albrecht
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Re: Multi Unit Dwelling

Postby S M Piner » Fri Jun 26, 2015 11:24 am

Thanks Albrecht.
will take a bit of working through I think.
S M Piner
 
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Re: Multi Unit Dwelling

Postby S M Piner » Tue Sep 15, 2015 3:53 pm

Hi Albrecht

I have worked through this building and got most of it working. The boundary side walls are strapped & lined so have been able to insulate them. However the end walls which face north & south which consist of double glazed joinery units between 240mm thick concrete walls in front of 400mm sq columns & 500 wide beams at floor level are causing a problem as the client does not want these strapped but wants to see the concrete structure.
Using R = 0.504 based on 100mm thick structural concrete having R value of 0.06 and the total wall thickness being 640mm giving the following:
Rse + 0.03 + Rconc 0.384 + Rsi 0.09 ( NZS 4214 values) I can make it work but is this an accurate calculation for these concrete walls??

regards

Sharron
S M Piner
 
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Re: Multi Unit Dwelling

Postby S M Piner » Tue Sep 15, 2015 3:56 pm

Just checking the calcs again and there is an E3 requirement for single skin masonry walls of 0.6 which I don't meet... :(
S M Piner
 
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Re: Multi Unit Dwelling

Postby Albrecht Stoecklein » Tue Sep 15, 2015 4:14 pm

Yep, your calculation is correct and also the fact that is has to meet E3 is correct :?
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Re: Multi Unit Dwelling

Postby S M Piner » Tue Sep 15, 2015 5:00 pm

Thanks Albrecht,

one problem down - one to go!!
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Re: Multi Unit Dwelling

Postby sunsetbeno » Fri Dec 07, 2018 2:02 am

Hi, just wanting to know if when calculating an addition to a block Masonry House, do I use the Minimum R1.9 for the existing Masonry Walls or is there a different minimum value for solid walls. Thanks
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