Monday, May 31, 2010
Because the building is constructed on posts, we were keen to make sure that the floor was insulated and enhance the protection against fire.
So our first job was to attach 27 2400 X 1200 sheets of fibre cement butted together on to the bottom of the joists between the bearers so as we could easily sit insulation batts on top of them before laying on particle board flooring.
As we had chosen to use joists set 600mm apart rather than 450mm the timber specified was only 35mm thick rather than 45mm. Now for all Turpsys great work there were of course discrepancies in distances between bearers and my measuring and trimming of the sheets using an electric saw fitted with an appropriate blade was not always as accurate. This would often mean that there was only not enough fibre cement sheet covering the bottom of the joists so nailing was out of the question and I would need to hammer a nail with a large washer around it to hold the two sheets up.
The height we were working with ranged from about 6 inches to 3.5 metres so the system we used needed to vary as we moved further towards the higher end of the platform. One of the most useful investments we made toolwise was a Paslode portable nail gun, and it was not only a god send for this job but for many others, as it is difficult enough to hold a quite heavy sheet in place without then having one person need to release two hands to place a nail in to a joist.
The first part was tricky because there was restricted space to work and we used a chocking arrangement and initally a normal hammer to fasten until there was space to use the nailgun.
Once we got to the middle section we could use our bodies to hold the sheets up so it wasn't too bad and we had our system sorted by then.
Once sheets need to be fixed overhead we needed a new system, which Michelle came up with, to hold the cement sheets in place while they were fastened.
This entailed drilling 4 holes about 50mm in from the side and a comfortable arms distance with from the ends so as thin ropes were threaded through for us to haul up the sheet and attach the ropes to other nearby fixings to hold the sheet up whilst it was fixed. This entailed Michelle, who is not missing an ACL ligament from a knee and a better head for heights, balancing precariously above me on the joists whilst I used the nail gun underneath. Before starting to do so, I make sure to let her know so as she could get out of the way because occassionaly I missed the joist and the nail would shoot straight through the sheet!
It was a buggar of a job taking us about 4 weeks to finish as we both work part time so that meant a maximum of 4 days on the building site.
As we are in a fire zone ( a block in the middle of a Karri forest basically ) there are certain requirements relating to house construction.
Apart from the usual planning, building and health approvals, we were also required to assess the degree of fire risk at our property before we could obtain a building license.
This involved getting a copy of the Australian Standard AS3959 ( Construction of buildings in fire prone areas ) and using the procedure outlined to make an assessment. This then needed to be submitted to the local shire council building inspector who then completes his own assessment and makes a final decision as to the level of construction required.
The following will give you some idea of what was required.
There are five categories of bush fire attack that are used to determine the appropriate level of construction to be applied to a development:
The categories of attack are determined by:
The type of vegetation
How close your building is to the vegetation
What the effective slope is (i.e. fire runs more readily and with greater intensity uphill).
The Fire Danger Index applicable to the region
Depending on the outcome of the assessment there are Level 1, 2 or 3 construction requirements.
The various categories and bush fire attack and the associated construction requirements are outlined below.
Minimal attack from radiant heat and flame due to the distance of the site from the vegetation, although some attack by burning debris is possible. There is insufficient threat to warrant specific construction requirements, but residents should still do basic property preparation.
Attack by burning debris is significant with low levels of radiant heat (not greater than 12.5kW/m2). Radiant heat is unlikely to threaten building elements (i.e. unscreened glass). Specific construction requirements for ember protection and accumulation of debris are warranted (Level 1 construction standards).
Attack by burning debris is significant with an increased radiant heat levels (not greater than 19kW/m2) threatening some building elements. Specific construction requirements for protection against embers and radiant heat are warranted (Level 2 construction standards).
Attack by burning debris is significant and radiant heat levels (not greater than 29kW/m2) can threaten building integrity. Specific construction requirements for protection against embers and higher radiant heat are warranted. Some flame contact is possible (Level 3 construction standards).
Radiant heat levels will exceed 29kW/m2. Radiant heat levels and flame contact are likely to significantly threaten building integrity and result in significant risk to residents who are unlikely to be adequately protected. The flame zone is outside the scope of AS3959 and the NSW Rural Fire Service will recommend protection measures in addition to minimum Level 3 construction where the applicant does not provide an adequate performance solution. Other measures such as drenching systems, radiant heat barriers and fire rated glass may also be required.
I assessed our block at level 3 but the building inspector was so impressed with the clearing we had done that he assessed it at Level 2.
The details required for each level of construction are well described in the following brochure produced by ACT Planning and Land Authority.
We had considered that we might attempt to build the house ourselves because our budget was very small.
As I have already mentioned, the block had quite a steep slope on it and there was now an added difficulty as the house was skewed across the block to take advantage of the northerly aspect so setting out the footings was going to be something that we were better off getting someone with appropriate experience to do.
Our architect had recommended a builder known as Turpsy to build the house for us as he specialised in homes that were built on steel poles so we engaged him to do the foundations up to the joists with the notion that we would take over from there!
I was stunned when he first came out to check the block out and informed us that the high point of the house would be 3.5 metres above the ground. The slope just did not look that steep!
So the first step was to get the footings in for the posts.
Turpsy bought in his crew, which included his son, and I was astounded when they set to work digging all the footings by hand including 4 huge ones that needed to hold up Michelle's end of the house.
This occurred because Turpsy, Michelle and I decided that rather than tacking a carport on to the back of the house it would make more sense to use the space underneth, so he redesigned the bearer layout and footing dimensions to accommodate the change.
You can just see the extra length engineered spans and larger footings supporting the high end of the platform.
Turpsy and his team did an amazing job especially with the fabrication of the steelwork not even bothering to use the adjusters often used to but relying on his accurate levels takings to get the correct pole heights. A couple of mini cement mixer loads and within a couple of weeks it was all completed.
So now it is our turn, as nearly $40,000 of our budget had disappeared already, so we are going to have a crack at doing the rest of the building ourselves.
This is the second time for m,e as I built most of a large two storey extension on a former home in West Leederville, and basically the first time for Michelle.
As I mentioned here there was alot of work to do to clear the block of some smaller bushes and trees and years of built up tree debris which needed to be raked up and burnt off.
We started this in September of 2008 and I reckon it took a good 6 weeks to get it cleared.
Also during this time we got the tree lopper Albert in to take down a quite a number of the larger trees which were Karris mostly.........
including a huge one.
Of course the poodles had to get involved also.
and we had plenty of wood.
Following consultations with our builder Turpsy, we also needed to get a digger in to remove some rocks so as we could get the footings where they needed to go and we ended up with a fantastic big rocks which Michelle got the driver to place interestingly.
Now we have all these wonderful big rocks and lots and lots of smaller ones too which is terrific as the bottom of the block does not have a fence all the way across the block so Michelle decides to build a dry stone wall.
This is really heavy work but Michelle treats it as a sculpture and gets heaps for herself out of the experience.
As there were only enough rocks to cover a certain distance, sections of split large rounds and the complete smaller ones from the felling of the trees were used to span the rest of the distance and it looks awesome.
Following the death of my mum in March 2008 and the completion of the administration her estate we were ready to go ahead with the move to Denmark.
Michelle and I knew pretty well exactly what we wanted in a house that would suit the range of our interests.
It is a basic and cost effective ( budget $100,000 ) design constituting a large space at one end for her ( the artist ) and a large space at the other end for him ( the musician ) with a bit in the middle to share.
Here is one of the sketches that Michelle made showing a design with a walkway between the rest of the house and her studio.
One of our surf buddies Pete Jongen is an architect and he had mentioned that, incredibly generously, he would be interested in drawing up a design for us based on our requirements in return for the creation, development and ongoing maintenance of his design studios website.
We took our little sketches around and he quickly roughed out some designs with a massive deck as shown in the image below which was something I really wanted.
So pleased with what he had proposed we left him to it and a few weeks later this is what he had come up with.
And so the building odyssey commenced!