A frame rises up!

Over one and a bit days (we probably could have sqeezed it into one LONG day) we got the inner ring of posts and the connecting ring beams up, as part of the house frame.  I was determined to not see the year end without having anything up, so we went ahead, despite the forcast for a very hot day today (luckily we finished up by 10:30am!).

Despite the weight of the timbers, and the complexity of the angles involved this first stage went up quite easily.  We used a home made 'lifter' which was built of timber and used a boat winch (all rated to well above the weights in our timber).  This worked quite well, the hardest part about using it was dragging it around the house site (nothing Brad builds is lightweight!!!!). 

The bracket on the post, this connects the post to the ring beam and the main beams, and involves several angles.

first post going up! 

We put up the first post, and found that the slots needed to be cleaned out a little with our electric chainsaw, to get them to sit down far enough on the stirrup to feed the bolts through the pre-drilled holes. 

Cleaning out the slots for a better fit. 

 Most of the other posts were cleaned out before they went up, but a few had to be done whilst hanging there....  After bracing the first post, we put up the second, and then the ring beam that holds together the inner ring of posts. 

The first ring beam in place

the frame taking shape

 The ring beam is structurally one of the most important parts of the our house design, as it stops the weight of the roof from spreading out the posts and collapsing.  From then on it was just a process of putting up a post and then the connecting ring beam, around the circle.  10 posts and 10 ring beams all up.  We were lucky to have my mother down to entertain the kids and a couple of friends helped for the afternoon/evening with actual building.  Thanks so much!

the beauty of natural timbers

the last beam 'slips' into place

This stage was a bit of a test of the design and our accuracy with everything we have done so far.  If any calculations had been done incorrectly, it would not have gone together properly (if at all!).  The stirrups were concreted into the ground and we could not test the fit of the posts on the holes until we actually started to put them up (they were just too heavy to move around too much).  Its a credit to Brad that this part of the frame went together almost perfectly (we had to fiddle around with a few posts/beams to get the bolt through - but nothing serious).

Yep, we are excited!

So the first stage is done, next stage is to get the main beams from these posts to the central collar.  That stage will involve a tower, pullies, and a few other low tech gadgets!

the central collar

Preparing the posts

Since we got the timber a few weeks ago I have been trying to work out a) how to handle the timber and b) how to cut it up. The posts are unseasoned 200mm x 200mm (8" x 8") x 2.7m dense hardwood. As mentioned in an earlier post they weight around 150kg. The main beams are 300mm x 70mm x 4.8m.

The first challenge was to move them around and handle them. The came in packs, there were 2 packs of the posts and then the several packs of mixed beams, ring beam, purlin and fascia. We have started to sort the mixed packs out into their own stacks and in the process putting spacers between the timber so that air can get around the timber and help minimise uneven drying and warping. To move the bigger timber members we purchased a furniture trolley with big heavy duty wheels. Myself and Sharon are able to load the timber onto the trolley and between the two of us are able to move the timber to where we want.

The next step has been cutting the timber up to use. We are going to put up the center ring first and then the outer. So we started on cutting up the center posts. This requires cutting the bottom flat and the top on a ~7° angle and then a slot in the top and bottom that is 200mm deep and ~10mm wide. We tried a few different methods for cutting up the big timber

1) Chainsaw - this worked ok, it was the quickest cutting but the draw backs are you have to be careful that you are straight as it does cut quick. The chain tends to chip the timber at the cut and the last thing is that it covers the timber in chain oil.  It also requires maintenance, checking fuel/oil, sharpening and starting.  It uses fuel, is noisy and creates fumes.

2) Handsaw - this method is quite slow, but it is quite accurate as you can monitor the cutting as you go along (usually while giving your arm a rest). the cut is nice an clean with minimal chipping at the edges. I use a Spear and Jackson crosscut saw with 10ppi.

3) Circular saw - The biggest circular saw that you can get from a hardware store appear to have a cutting depth of 85mm, so drawback of this method is that you end up with a bit in the middle of the 200mm post that the saw can't reach. Also the post faces are not exactly perpendicular with each other and vary in size from 190mm to 205mm (so far these are the 2 extremes I have encountered).

The method I have ended up using is a mix of 2 and 3. so I circular saw as much as I can and then finish off with the handsaw.

Marking up the posts has been the most important thing, and as mentioned the posts are not square. The most important part of cutting up the posts is the height and that the slots at each end line up with each other, if they are at an angle to each other then the top bracket will not point to the center of the house which is a big problem. So to line up the slots properly I ended up choosing the face of the post which will face in toward the center of the house and then measure a constant 100mm (to the center of the slot) for all post no matter what the actual diameter was for each post. This will give me a constant distance from the center to the face.

To cut the slots we very carefully marked them up making sure that the top and bottom slots lined up. We did this by marking up the top and bottom together, the distance from the face was the same for the top and bottom and we used a tape measure from top to bottom when marking them. When both sides of the slot were marked we then joined up the side markings along the ends. To cut we used a circular saw. A cut was made on each edge of the ~10mm slot on both sides of the post, the big thing here was to make sure that the saw depth cut was inline with the end marking since each face of the post is not guaranteed to be 90° to the others. I did this by lining up the saw blade angle by eye with the slot end markings and then watching as the saw cut that it was staying true, if not I would account for the difference by slightly tilting the saw while cutting. The top of the slot was pre-drilled using a 10mm auger bit and the material left in the slot was hand sawn out using the crosscut saw (I will have to look around for a rip saw I think, since the crosscut while it worked took a while to get through).

The other issue we had was to drill a 'straight' hole through a 200mm chunk of wood. My drilling is not that accurate that I was confident of doing this for every hole (each post has 4 holes). The stirrups and the top brackets are all pre-drilled with 18mm holes. The bolts are M16 so there is a 2mm allowance for error. Since the timber is green this will allow for some shrinkage too. But because the steel is drilled we have to get the holes in the timber pretty accurate, a crooked hole would look bad but more importantly it will probably mean that the bolt won't fit through. To solve this problem we ended up marking the hole on both sides of the timber off the front face, this involved using a square on the face and measuring the opposite hole from the square, which should align the hole exactly perpendicular to the slot. We then drilled the hole about 3/4 from both sides. any slight variation on each of the holes was then 'adjusted' by re-drilling so that the two hole match up. We bought several sized augers and have found that they are brilliant for drilling nice straight holes through the timber, they literally pull the drill through the material.

We have now cutup the first 10 center posts and they are ready to put up, but before they can go up we need to cut up the ring beam timbers (240mm x 70mm) and get the top bracket made up. The top bracket joins the top of the center posts to the inner and outer main beams (these beams radiate out from the center) and the ring beams (they join all the center posts together).

Our timber has arrived

Yesterday the first truck load of our timber arrived from Bowerbird Timber.  Our house is of a post and beam construction, so instead of the typical pine framing stud walls that most houses are built of, this house will have 20 posts, and then beams between them.  As its a circular house, the posts are arranged in two circles and there will be a central collar where all the beams meet in the middle. 

The timber we bought is Coastal Grey Box and its a very durable and heavy timber.  The timber is quite large, the posts being 200mm x 200mm, and too heavy to lift (approximately 150kg each).

So the next challenge will be building some lifting gear to lift these posts, and the beams into position.  That and cutting all the slots into the timber (and doing it accurately!).

Mud and wheelbarrows - the footings

We were incredibly fortunate to have a small group of helpers (both family and friends) to assist us with our first concrete pour last weekend.  We were incredibly unfortunate to have ALOT of rain the night before the pour, so after concerns about it being too hot to pour, we had concerns it would be too wet!!!

Our stirrups - these things are built to last!

We spent most of a week preparing the site, and having our site inspection (which we passed!).  To make sure that all our stirrups would be lined up perfectly and would be easy to get right and check once the concrete was poured, we spent many nights discussing and brainstorming how to make it work on the day.  We decided on bolting 2 pieces of timber to each stirrup shank, tight enough so that it would not move.  This timber would sit on the ground, and the height could be adjusted by loosening off the nuts, and pulling the stirrup up or down.  This meant that the height would be right.  To make sure the exact location within the hole was right we set up a string line with marks on it, and once they were all 'perfect' we sprayed the ground and the wood with marking paint, so that the position was clear, even if the stirrups were removed from the hole.

How we braced the stirrups and lined them up ready for the concrete.

As it turned out, we had enough people so that some were to push barrows full of concrete, while 2 would stand of the timber supports to hold the stirrup in place as the concrete was poured in.  The 'holding person' also was able to help with tipping the barrow.  Although the stirrups and the supports got a bit in the way, the whole thing barely moved, so it was just a matter of going through and double checking them all after the concrete was poured, and reduced the stress levels considerably, as we didn't have to stuff around putting stirrups into concrete and lining them all up afterwards.

Pushing wheelbarrows full of concrete through the mud, not an easy task.

We had 20 holes all up (so therefore 20 stirrups), in two circles, which we call the inner circle and the outer circle.  At each of these we will fix our posts and then the beams will radiate around to a central collar.

double checking the distances after the concrete was poured.

Our concrete pour was a fun day.  It was muddy and difficult (the mud clogged up the wheels of the barrows, so they were really hard to push or control), but there is a sense of comradery when doing a task like that with a group of people, especially when everyone can work well together as a team.  We are indebted to all that helped us that day.  It was all over within an hour or so, but it was fast paced and challenging at the time. 

How the wheel of a wheelbarrow looks after numerous trips through the mud.

Next step - the frame!


A huge thank you to Paul, Grant, Pete, Karhen, Claude and Margit for your help!

Site preparation

Preparing the site was the first step.  We hired an excavator/bobcat operator (we hired him before to do our driveway a few years ago), and it took him 3 days to complete the job.  Its incredible how much soil has to move, even when a site looks pretty level. 

The work involved leveling a pad for the house to sit on, putting in some drainage to keep run off away from the house, drilling 20 holes for our pier footings (the posts for the house will sit on these), and creating a turning area for trucks and cars to turn around (very important for a building site to have good all weather access for delivery trucks).

Its quite amazing to watch a good machine operator, the ability to do such fine detailed work with such big machines.  Our little boy was mesmerized by the work, he could have sat there for 3 days straight, and would still have been sad to see him go!

 

So step one is complete, next step - see what the inspector thinks!

The begining

Five years ago we designed our house, as part of our planning permit application.  We had been interested in alternative energy, sustainable lifestyle and natural building type stuff for quite a few years, and we were enthusiastic to start. The design was for a modest home, not too big, well insulated, practical and a bit different. 

Earlier this year, we made a start on getting the our plans to the stage we could get a building permit.  The process took 5 months, and was not the most enjoyable experience.  So many steps along the way, soil tests, bushfire assessments, engineering reports, energy ratings, and final plans.  Each one of those comes with a price tag, and you just want to close your eyes sometimes, it hurts the bank account!

It probably didn't help us that we weren't building a run-of-the-mill brick veneer home in the suburbs...  Little mistakes like the building designer/draftsman getting the size of strawbales wrong, to them not understanding the concept of a 'mud room' and that we actually wanted the back door to come through the laundry!

We thought alot about the design to make it as energy efficient as possible (no doubt there are mistakes in it that will become apparent once it starts to take shape), small windows except on our north side (south for those in the northern hemisphere) were we have a sunroom and lots of glass.  Orientation is the easiest thing to get right in designing a house, and the hardest thing to fix once its built.  It has big impact on how livable a house is (we lived in a poorly oriented house for 8 years), and yet has little if any impact on the energy rating that a house has to get to be approved. Other important features of our design that had no impact on our 'energy rating' were the thermal mass in the walls and floor (that help even out the temperature), and the fact that the house will be running on solar power!  Hopefully some day these things will be incorporated into these energy ratings, and perhaps the rating will actually reflect the true energy efficiency of a house.

So as of October 2010 we are now owner builders, with building permit in hand.  We have built the house of paperwork, now for the fun to begin!