Rafter day!

The rafters went up on 25 Chapman Place yesterday. Suddenly the house has started to look like it's going to end up.

Looking in from the top of the driveway. The open carport will be tucked in underneath the eave at the front of the house, providing a covered entry.

As soon as the rafters went up, you could immediately get a sense of how the house is going to look and feel from the inside.

This will be the view when you are standing at the galley kitchen bench, looking across the living area towards the deck, and out into the trees beyond. You can see the hole left for the double sliding glass doors.

The outlook across the deck towards the east from the living room doors - you can see all the way to Archerfield. This view won't be blocked when Number 27 is complete.

Let's talk steel.

Here I'd like to talk about hot dip galvanising compared to DuraGal. It’s a big issue, there’s lots of marketing out there for DuraGal, and it's a popular product. So, what's the difference?

Nice fresh hot-dipped galvanised steel columns for 25 and 27 Chapman Place.

This little pile of steel will hold up two houses... and cost over $12 000.

A few minutes on Google will find you specification information and some revealing case-studies about the differences between hot-dipped and DuraGal if you're interested.

Hot-dipped galvanised columns are made like this: the anti-corrosive galvanised coating is applied after your columns have been fabricated, and it's applied by dipping the whole piece into the galvanising solution, covering every surface, every weld, even the inside of columns through the holes specially left for this purpose.

Here you can see the hot-dipped galvanised coating has completely enveloped every weld and hole of the column components.

I have designed these houses at 25 and 27 Chapman Place for the lowest long term maintenance cost, and that's why I'm using hot dip galvanised columns, as it offers the longest corrosion protection. The catch? It’s twice the price of DuraGal and can take an extra two weeks from ordering - which are the main reasons that others might not use it.

Down in the dirt... foundations.

Foundations are expensive. Why? They're the most important part of any house. I've designed these houses to sit on steel columns for a couple of reasons, which I'll outline below.

The first, and most important consideration was termites. Yes, there are termites here in Oxley. They're everywhere, and they can't be eradicated from the environment unless you could treat the whole street, and the whole suburb, and the whole of south-east Queensland, and even then they'd probably have made their way back in a couple of months. That's just what they do.

Termites are the cancer of the house world. In slab-on-ground construction they are difficult to prevent. They only need the smallest of entry points and they are in. Column construction does not require the use of chemical barriers (if you have concerns about chemicals in the home environment then this might be an issue for you, particularly if you have young children), or rely on the integrity of barrier systems.  Also, the owner is not required to pay the ongoing 6-12 monthly inspection fees to maintain the warranty of termite prevention systems. However you do need to check with your insurance company on their requirements to maintain insurance coverage. As not all termite species require a connection to the ground,.. and there are other insects such as borers that can attack timber. (Treated frame timbers are a must in my opinion.)

Another important consideration I made when choosing to go with steel columns was the ground conditions. The engineer in their design process conducted a soil report, and for both sites this came back as 'H', which means the ground is highly reactive to moisture changes. So, if the houses were to be slab-on-ground, the design would have to try and resist these ground forces. That's a fancy way of saying that the soil around here is in fact solid clay, which has a bad habit of moving about and shifting your house. Ground movement causing unsightly cracking in brick construction is a huge problem within the industry.

Here I have used adjustable tops on the columns. This means that should the worst happen and the house does move, these adjustable tops can be raised or lowered (using a really really big spanner) to return the house to level. To be honest, I don’t expect this to happen as I always take particular care with the foundation material... really they are there as insurance. This is the first time I have used adjustable tops, the main reason being that I hope these houses to have a very low ongoing cost to the owner in the long term. So, this means planning for the worst case scenario.

For 25 Chapman Place, the holes averaged between 2.5 and 3 metres deep. I ensured all holes were drilled through the highly reactive clay, and into a consistent fine material as shown.

Additionally as the holes were so deep, I had to use a vacuum truck to clean the holes of all debris. The drilling process of the hole by an excavator does not remove all loose material, because as the auger is removed soil falls back in the hole. It’s common practise in the industry not to remove this, but rather tamp down loose material in the bottom of the hole, which can result in your house sitting on 100-200 mm of disturbed material. Why don’t all builders clean the holes properly? 'Time equals money' is the simple answer, as it’s a time consuming process and not a very nice job to do. On this job the cost of the vacuum truck alone was close to $2000.

A typical hole on this site, nice and clean! You can see where the auger has scraped up the side, which shows that it goes down down down through the clay, until suddenly towards the bottom (that's at least 2.5 meters deep down there - tricky to photograph!) it changes to a decomposed rocky sub-soil as shown in the earlier photograph.

Here, at the bottom of this hole, you can see the drill auger centre hole. This is what a hole should look like if it's been cleaned out properly - you can see the mark of the auger in that patch of sunlight at the very bottom of the hole. No debris!

Flexibility is also another feature of steel column construction. Should the buyer want to add power or data points (something to consider is this age of rapidly changing technology), change the kitchen or bathroom, all services are easily accessible. This saves the home owner money in the long term. Also  issues like blocked drains are simple to fix as all is easily accessible. The possibility of raising the house sometime in the future is also a viable option with steel column construction.

Another advantage of putting the house up on columns is that the underlying ground has not had to be either cut into or built up. The natural ground levels have been preserved. This means that potential problems with pooling water or unnatural run-off for either these or neighbouring properties are largely avoided. It's an environmentally-sound thing to do, to work with the ground you've got rather than shaping a piece of sloping land into a piece of flat land: no excavators, no digging, no retaining walls, no fill. Building on columns is not necessarily the cheapest thing to do - which is why slab-on-ground construction is most common for entry-level housing.

The initial site preparation for 25 Chapman Place. No cutting in, no building up.

The place – Oxley, Brisbane, Queensland.

Numbers 25 and 27 Chapman Place are two elevated residential blocks in a recent land subdivision in Oxley, Brisbane. If you're looking for them on Google maps they're indicated by 'Lot 1' rather than 'Lot 25' as tagged by Google.

Oxley is a surprising place to live. (I should know, I live at 29 Chapman Place.) Seventeen Mile Rocks Park on the Brisbane River is a new park on the old Queensland Cement loading site. Longtime residents of Brisbane might remember the barges navigating their way up and down the river from Moreton Bay. This is the place where they offloaded, and it has now been converted into a vast landscaped area of riverside public parkland including a popular children's water play area, community vegetable garden and picnic zones. The design of the park has preserved quite a few features from the concrete plant which now serve as an interesting reminder of its recent industrial history.

Oxley has great transport links with the main train line running through it, and easy access to the Ipswich Motorway, and the Centenary (Western) Freeway, which links to the Logan Motorway. The new tunnel at the Toowong end of the Centenary Freeway will ensure easy and fast access to the airport should you choose to drive and not use the train.

Whist some low-lying parts of Oxley were affected in the devastating Brisbane floods in 2011, Chapman Place is on the southern side of Oxley hill, and was well high of any of that dreadful water.

The plan – 25 and 27 Chapman Place, Oxley.

It’s not an easy task to design a house to give potential new owners flexibility to adapt the house to their lifestyle.

The design for 25 and 27 Chapman Place is a hybrid of a traditional Queenslander (a central hallway, three bedrooms to the front, living space out the back) and a modern beach house (a simple roof line, louvres, and modern interior).

The floor plan for 25 Chapman Place. The floor plan for both this house and 27 Chapman Place features three bedrooms to the front of the house, with the master bedroom including a walk-in robe and en-suite bathroom. There's a second bathroom and laundry off the central hallway, which opens out into an airy kitchen and living area, and covered deck to the rear of the house.

The north elevation of 25 Chapman Place. Here you can see the simplicity of the single-plane skillion roof.

The north elevation of 27 Chapman Place. This angled-edge facade will be clad in iron, lending a very modern look to this house from the street.

The skillion roof line lends itself to easily extending the house at a later date should the need arise. The open carport design allows for flexibility for the new owner; you might have a boat, caravan, or trailer that you would like to be able to park behind the carport, or you might like to build a workshop in the space. It's up to you.

The intention with both these houses is to offer the entry level buyer a high quality product. Thank you so much for your interest, and I look forward to sharing the process with you.

Carl.