ECOTECT NEWS 006 - 12/11/09
A lot to report of progress these last 10 months or so. Both the Tasman District Council (TDC) and Nelson City Council (NCC) have approved a revised Alternative Solution submitted by Ecotect Ltd with now several new house and renovation building consent applications.
This Alternative Solution allows the use of standard H1.2 Boron treatment of Douglas fir rafters in low pitch and flat skillion roofs under both sheet steel roofing and Butynol on ply. The solution also allows the use of Douglas fir cavity battens treated with boron to H1.2, both situations usually require H3.1 or higher treatment which is always provided with toxic chemical treatment. The cavity battens are best used with claddings that are fixed with drilled nails or screws as they tend to split.
Solabode 002 on an exposed Moutere hills site has been occupied now for a few months and is looking great inside and out. The owners report higher than expected costs and so from discussions with them I have reconsidered several aspects of the design to reduce costs further.
The clients have also expressed overheating in the middle of winter which, while this can be moderated with careful ventilation through the high fanlight windows, seems to be a slightly inconvenient side effect of simple direct gain passive solar design. But at least it is better to be too hot than too cold in winter when outside temperatures are around 5 to 10 degrees. A couple of sun screens can be used for when seated at the dining table etc to reduce glare.
Solabode 001 in Takaka is almost complete and the clients report costs within expectations and very good internal comfort at all times even though curtains have not yet been fitted. Next winter though will be the real test for this home. Recently the Tung Oil natural floor sealer was applied to the surface pigmented concrete slab floor, this product is 100% natural, toxin and odour free and is easy to apply, I am very excited about seeing the final results of this application as it is the first of many projects specified with this product and not used before in the south Island for such use, as far as I am aware.
Solabode 003 is being drawn up as I write with building start programmed for mid to late summer. The house will be located on a semi rural north facing sloping site in Geraldine, South Canterbury. Several design changes have been made to this home in response to the harsh winter climate and from lessons learnt on the other homes built. For example a steep pitch truss roof to shed snow and reduce costs but with a sloping ceiling maintained within. The design features three bedrooms or really 2 bedrooms and a study, but only one bathroom as the clients have no need of two. Adobe veneer walls for thermal mass have been included in the main living room and solar access space but left out of other rooms to reduce costs. Glass louver windows have been incorporated above internal doors to distribute warm air throughout the home. Finally, insulation levels have been increased to R6.8 in the ceilings and R5.0 in the walls except the north wall left at R3.2. Underfloor and perimeter insulation has been doubled to 100mm thick.
The Baden house is progressing very well with Builder Phillip Hay on the job. Of particular note are the fabulous internal 2 storey high exposed concrete masonry walls using charcoal coloured honed surface blocks laid in stackbond pattern. These walls are for thermal mass, noise control, structure for floors and roofs and are the finish without any need for paint or linings. We will be experimenting with the Tung oil sealer for a semi gloss finish. See the Baden House for recent photos.
Several other projects have been completed in recent months and I will report on those at a later time.