Our Dream Renovation: 06 Subfloor Frame

Now that all the dirty work is done, I am excited to go back to my trade background (carpentry) and start building the subfloor frame! But first, I need to set the bricklayer up so he can get the piers and the garage subfloor brickwork built.

Building The Brick Piers & Subfloor

Before my bricklayer could start out on site I needed to go and transfer some marks down onto the concrete pads for the brick piers. Firstly, I had to set up my stringlines. Thankfully I had the profiles still in place from the excavation stage. I was the. Able to plumb down off the stringlines to get every external corner and internal corner of the house for the piers. In some cases I could directly plumb down to get my mark, in others I had to plumb down and measure across to get the mark. It all depends on how I had set up the profiles.

I decided to set my brickwork in line with my wall framing. Just to clarify, I have the intention to eventually run 20mm slats to half enclose the subfloor. The wall cladding I am using will roughly be 20mm off the wall frame. This means the slats will be in line with the cladding, looking seemless.

With the footings all marked out the bricky is nearly ready to go. My next job was to calculate my floor heights for him to build to. To do this I work back from the R.L on my floor plan. From the R.L I deducted my flooring thickness, joist height and bearer height resulting in the height of my piers. Because I was working off an existing structure, I was able to get my bench mark off the exisiting floor. In other cases, a surveyor may need to give you a bench mark for a starting point.

I ordered the sand and cement and booked my bricklayer in to make a start. He had a 7.0m x 3.7m subfloor to build and 80 piers. All up, around 3500+ bricks had to be laid.

Building The Floor Framing

Finally! … I can whack on my tool belt with cause. I took delivery of my bearers and joist and got cutting and nailing right away.

I decided to use Hyspan LVL 90×63 for the bearers and the 90×45 for the joists. I have worked with this floor system before. So, it went down really easy.

Hyspan LvL 90mm pros

• Creates a smaller in depth subfloor. In some areas of the build this saved me having to excavate more. As a result, I could achieve a 400mm subfloor from ground to bearers.
• Easy to install and light weight. I was able to install this subfloor framing system on my own.
• Termite treated. Our brand of LVL used was called the terminator.

Hyspan LvL 90mm cons

• Smaller spans, which means more piers and more concrete footings.
• Other then that I cannot think of any other cons, I will be sure to add any that might come to mind.

Tips to installing joists: Always set out the bathrooms and make sure the joists don’t land where the toilet stack is. Ensure you have joists or blocking installed where your point loads are coming down from the floor and roof. Always install double joists along the external perimeter of the house and block out around the external perimeter.

Laying The Flooring

Unfortunately installing the flooring is not very thrilling to talk about. I used the yellow tongue flooring sheets, glued down and nailed to the joists.

I picked the longest run, flicked out a straight line and started laying it down!

Subfloor Frame Stage Costs

Total Project Costs To Date

• (02) Designing and planning stage: $13,428.20
• (03) Council application stage: $6,171.20
• (04) Excavation stage: $1,163.82
• (05) Strip footings & piers stage: $3,079.13
• (06) Subfloor frame stage: $12,542.85
• Total costs: $36,385.20