Significant Progress

Bathroom external wall rendered

Rain chain and more finished walls

Having a renderer that has been able to give some full time attention to the house has led to significant progress being made over the last few weeks. The internal walls are finished and there are only three external walls, three upper walls and a small section around the front door to go.

Freshly rendered back wall

Front of house freshly rendered

The hemp lime rendering  has not been easy. The window headers have been particularly difficult as the render is not very sticky and so tends to fall off the window headers, the render also does not spread very well and so cannot be moved around on the wall, it also tends to get rougher if you go back and try to touch it up.  But Brett, the renderer, persevered and has managed to do the window headers by filling any gaps or holes first (particularly any patches where chunks of the hemp wall have broken away or crumbled), then when this is dry he has attached a straight edge to the window and finished the underside of the window header, then when this has gone off a bit he has gone back and done around the face of the window header. The window headers have been done the day before the wall has been rendered. Then when the wall is done the sides of the windows or doors have been done first followed by the face of the wall. 

Patching the worst of the holes in the window header

Window header rendered

 The walls were wetted down before being rendered, then sprayed with a light mist of water on the evening after the wall was done on warmer days or the next day, to slow the drying down.

The hemp render was not suitable for use on the Magnesium Oxide (MgO) board at all. It had to be done in two coats, increasing the cost. The MgO wall could not be wet down first otherwise the render just slid off. Even then the render had great trouble sticking to the wall and if done too thickly would bubble and fall off or crack and just slide. The last MgO walls were done by splattering the first coat on which seemed to work better, but it was a bit late in the project to worth this out.  The second coat of render on the MgO was very difficult to work and on most walls the finish was very patchy both in texture and colour.

Left - Hemp render on MgO Board and right- hemp wall

Hemp render on MgO Board

With only a few walls left to do the render will be finished in a few weeks after Brett takes a break from the hemp walls, with a few more conventional jobs. The completion of the internal walls and the external walls, that have lights on them (thank you Brett for doing those walls at short notice), meant that the electrics in the house could be finished. Paul and Luke from Solar Connections came down and fitted all the internal and external wall lights and got all the power points working. A small problem arose when the back circuit and stove circuit would not work. I panicked that there may be a problem with the wiring in the wall or roof and I would have to start pulling the ceiling down to find it. Thankfully this was not required, but a mix up of the stove and dishwasher power points will hopefully be resolved by long cords on these appliances or a short extension cord hidden under the cupboards.

External light installed

Front of house with external lights installed

 I had forgotten about the LED lights under the overhead kitchen cupboards and so spent much of the day putting up the cupboards so the electricians could install the lights. The LED lights were made up to fit the length of the cupboards, leaving a gap for the range hood over the stove.  

Kitchen cupboards and LED lights underneath

Everything happened at once as on the same day the electrics went in, Brett was rendering the external walls and Greg from Alpine Glass put the semi frame less shower screen in the front bathroom. Plus he helped me out by drilling the holes in the tiles for my toilet roll holder, I had been scared to do these for fear of cracking the tiles. With the right drill bit and experience it was no problem.

Semi frame less shower screen

Toilet roll holder

The completion of the internal rendering meant that the final finish on the floor could be done. Before this could be done I had to remove all the boards and plastic protecting the floor and remove the tape and clean the excess render from around the edges of the walls. I used vinegar and hard work to clean up the render from the edge of the floors and had to vacuum and mop the floor several times with multiple changes of water to get rid of all the fine dust. 

Floor in need of more mopping

Cleaned concrete floor

 The first coat of finish on the polished concrete had what looked like crazy paving type pattern cracked in the top of it. This was only visible when light hit the floor at an angle but was much more obvious under artificial light. There were also a few patches of white spots and some rough sections where things had fallen on the floor when the first coat was drying as this was done before the windows had been put in.  

Crazy paving cracks in sealer

White dots on concrete

Henry and Adrian from Dayman Group returned to fix up the floor. It had been two years since they did the first cut on the polished concrete and almost a year since the first sealer went on. The floor was given a light sand which will hopefully resolve the crazy paving cracking and remove the rough sections. A bit more of a sand was required to get out the white spots, which I was told were caused by the floor being covered before the first lot of sealer had fully dried. They also fixed up some patches which would have been covered by the kitchen cupboards, except that the cupboards we are installing are about 30cm off the ground. 

I left while the final coat of floor sealer was still wet and so am keen to get back down there and see what the final finish is like.

Ceilings and Internal Walls Completed

We had intended to do all the plywood ceilings in the house before the internal walls. However, over three ad a half months ago work on the ceilings stopped when we found that the remainder of our batch of BB hoop pine plywood had unacceptable blue stains. We took up this issue with the local supplier, Huskisson Ply.  After countless phone calls to Husskison Ply that were not returned, we even tried phoning the distributor Gunnersons. We were happy to swap the ply sheets for those without blue marks and even pay for the extra transport costs. After three months (!!!) I finally got a reply from Huskisson Ply that we could return the sheets less a 20% restocking fee. So we would only get back 80% of the cost of the sheets.

We resorted through the remaining 26 sheets of ply and measured and calculated exactly how many sheets we needed and the size of each sheet. We worked out that any sheets less than the full width we could use the back of the sheet, as many with blue marks on the front did not have them on the back, and cut off the manufacturers big purple stamps that were on the back of the sheets. Other sheets with only patches of blue marks we managed to cut around the marks, resulting in a bit more wastage as some sheets we could only use about 1/3 of the sheet.

In the end we returned 13 sheets, but due to careful measuring we only needed to purchase 10 new sheets. This made up for the 20% we lost on returning the sheets. We returned the unused sheets to Huskisson Ply ourselves as we needed to get them out of the house as they were in the way where we needed to finish the ceiling in the main room.

The new sheets came from Mister Ply and Wood at Penrith. I had dealt with Chris Carter from Mr Ply several times over the previous few years and should have got all the ply from them in the first place. Instead I chose to go with an unknown local supplier to save on transport costs and support local businesses where I am building. Since I was only getting 10 sheets I was able to pick them up and transport them to site myself, by trailer, saving transport costs. I was also able to go into Mr Ply and Wood and due to my previous poor experience they let me go through the sheets they had in stock and select the ones I wanted.

Main room ceiling half done

We are very happy with the result. The new sheets of ply have slightly less figure in the grain. In the bedrooms we love the interesting swirls in the ply, it was this unique feature of the wood that made us choose to do the ceiling in ply in the first place. However in the larger main room the less figure in the ply works better as it makes the ceiling less busy.

In the smaller rooms, such as the bathrooms, entry and hall we were originally going to have the black expressed joints between the sheets and put up the blocking and painted it black. However, when we realised that the smaller bathroom would only have one joint we realised that this would look a bit silly and decided to butt the sheets together with no express joint. In doing this I tried to match the machine cut joints together. I could not always do this, particularly where I was using the backs of the old sheets as I had to cut the manufacturers stamps off both ends. So I had to cut the ply very carefully and then sand the cut edge until it was perfectly straight, or as near as I could get it. Not doing the express joints meant that I did not have to paint the edges of the ply black, thus the ceilings in the smaller rooms went up quicker.

For the main room we also chose not to have a black border around where the wall meets the ceiling. This had worked well for the first two bedrooms we put the ceiling up in, but in the third bedroom one of the walls was not quite square and this upset the process of trying to get the black border around the room. This is something we will have to try to disguise with some creative rendering.

Butt jointed ceiling in the smaller bathroom

The ceilings in the laundry and top of the hall were covered in one sheet. This was very neat but required careful measuring as the frame along one of the walls in the back section of the house was not straight.

Ceilings covered in a single sheet

With half of the main room ceiling left to finish, illness in the family, looked like delaying the completion of the ceiling. With very good timing my mate Tony offered to come down and help out on the build for the weekend. Over two days the rest of the ceiling went up like a dream thanks to the panel lifter, the 9mm strips of timber used to measure the gaps, careful measuring and Tony's help. It was truly a joy to look up at the completed ceiling in the main room, reminiscent of Japanese Tatami mats on the ceiling.

Completed plywood ceiling

The internal wall sheeting had previously stopped short of the ceilings so that I could put the ceilings in first. With the ceilings done work continued on the internal walls. I had under estimate the number of screws required to put up the internal walls. The house does not have many internal walls, but some of the internal walls are quite high and the raked ceiling meant that none of them could be completed floor to ceiling in one sheet. The built in robes also required more sheeting that it first appeared. I initially bought from Nepean Boltmaster 1,000  x 30mm  and 200 x 20mm fibre cement screws. The shorter screws were for the sheets attached to the cavity sliding door units as the screws could not go through to the other side of the timber side rails of these units. I then bought 300 more of the 30mm screws. Then another 100 x 20mm and 200 x 30mm and a further 200 x 30mm to finish off the job. That adds up to 2,000 screws.

Almost 2,000 screws used

Internal in walls in bedroom and robe sheeted with MgO Board

Bedroom and robe MgO sheeting completed, in late afternoon sun

Before ordering the MgO Board I had done a rough drawing of all the pieces I would need and roughly worked out what pieces I could get out of each sheet. When I cut each sheet of MgO I cut the large pieces out first and worked out the most efficient use of the remaining piece. This way I used the MgO board much more efficiently than I had first calculated. I will have 8 sheets left over after I use one more for the bath hob. The left over MgO Board will be used for the ceiling of the shed I will build later.

Render Colour Chosen

We have decide to render the inside and outside of the house all one colour, to give the illusion that the solid walls are that colour all the way through, so the choice of colour will have a big impact on the look of the house. A light, but warm, yellow is the colour we are aiming for. Originally we were trying to achieve a sand colour until we realised how brown a lot of sand is.  Our light yellow is an idealised version of the colour of sand or chopped hemp fibre.

After initially dismissing the use of Builders brand oxide in 420 Yellow, we reconsidered it when compared to some paint swatches we got from the hardware store the other oxide colours we had tested were too orange or too brown. Our objection to the yellow was its intensity so we tried some very pale versions at 0.2% and 0.4% (Our earlier tests had been 1% and 2% but had been done with unreliable scales. Scales than only measure in 1g increments are not accurate enough when trying to measure a weight of 2 grams ). These tests did not give enough colour to overcome the underlying green grey tinge of the lime render mix. 

Further tests were carried out, both on the hemp wall and on the MgO  board, using 0.6% yellow, 0.8% yellow, 0.6% yellow and 0.2% sundance, and 0.6% yellow and 0.2% sandstone. These tests were measured out using a tiny tube cap as my jewellery scales ordered from e-bay had not yet arrived. Later after I received the jewellery scales, accurate to 0.01g, I found that one capful was 0.45g which when doing 1/40^th of a mix was 0.2%. We have done all our render tests on the wall behind where the kitchen cupboards will go, but were running out of room, so we used a hammer and cold chisel to chip off some of the render colours we definitely were not going to use. Pleasingly the render did not pull off easily and was well adhered to the wall, but ultimately came away with minimal damage to the hemp wall underneath. 

Top centre: Chosen colour 0.8% yellow

4th from left: 0.8% yellow on MgO and Top far right wet test of same mix

The further render test colours were all close together which enabled a finer comparison. Even though the colours were close together 0.8% yellow was clearly the best. The lighter yellow (0.6%) lacked sufficient colour, but any darker that 0.8% would have been darker than the “light yellow” colour we wanted.  As it was our chosen colour was darker than the paint swatches we were comparing it to, but it was difficult to make a direct comparison between different products. We checked the 0.8% yellow render against the plywood ceiling and the hardwood window revels and door jambs and the dark grey polished concrete. It was satisfactory against all these materials. We then moved the MgO board outside to see what the render looked like in bright sunlight, and it was still satisfactory. 0.8% yellow has tentatively been chosen. This will translate to 72g of oxide per 9kg bag of render. To check that we have got the measurements correct and can replicate the colour we like we did a further test of 0.8% yellow. We have yet to see this check patch dry.

It is fortunate that we have a render colour, as on the recommendation of our neighbours we met up with John the renderer. He was experienced with a variety of renders and was keen to try a new product, the hemp lime render. We realised it was unlikely that we would be able to achieve a consistent render finish and that it was likely, without experience, that the rendering would take us a long time.  Next time we are on site we have arranged with John to do a section on the inside of one of the wardrobes, so he can see what the product is like to use and work out the finish we want.  We used offcuts of the good ply to finish the ceiling of the robe so it can be sheeted and ready for rendering.

Wardrobe ceiling added

The last two of the cavity sliding door units have been installed. One of the cavity sliders that is not supported at the opening end by a perpendicular wall was a little bit wobbly as when the top and sides were level the bottom of the opening jamb was off the ground. I will have to find some thin masonry anchors to put through the bottom side rails into the concrete floor.

Cavity sliding door units installed

 With the last of the cavity sliding door units in we were able to continue with sheeting the internal walls. I borrowed some fibro cutters from a friend, Martin who has helped out on the build on several occasions. I was amazed that the fibro cutters were easily able to cut through the 8mm MgO board. I just had a little trouble cutting on my marked line and keeping the cut straight. I will practise further with the fibro cutters before I choose my preferred method of cutting the MgO boards.

Internal walls being sheeted with MgO Board

An unusual detail that we discovered while building the walls was that one of the studs at the door opening was set in from the line of the cast hemp wall. This meant that the wall was further out than the stud. When I came to install the door jamb it all worked out very well. I am using 19mm Tassie Oak for my door jambs. I used an angle grinder to cut into the hemp wall to enable me to set the 126mm wide door jamb flush on the stud. When the wall is rendered the 10mm render will come up flush with the door jamb and instead of being a problem this will now give a neat finish.

Hemp wall cut away with angle grinder

Close up of the cut away hemp

The large awning on the north side of the main room had a dip were the two parts of the fascia board were joined. I had been reluctant and unsure how to tackle this problem. My neighbour from home, James, was in Nowra for the weekend and we  recruited him to use his building experience to help us solve this problem. After some thought and discussion the shorter end section was removed and the longer section cut and 2/3rds of it removed so that a single long piece of fascia could be used to replace the pieces removed.

Awning propped and new piece added

 First we used some props to level the remaining pieces of the fascia. It was amazing to see how much the awning had dropped and how much more movement it had in it, since we installed it in January. Further props were added and levelled where the join would be and at the far end, this enabled us to rest the long fascia board on them rather than having to try and hold it. With everything level two batten screws went in at every awning rafter and a cleat was attached to the back of the join of the fascia, which was between to rafters, rather than my previous mistake of jointing the fascia on the rafters and not using a cleat. The result was beautiful. I can look at it proudly and see that it is level. Now I can put the battens on ready for the corrugated roofing to go on. I will also go back and re level and prop the other awnings and leave the props in place until I can put some steel cable in from the awning to the rafters of the roof above, to prevent the awning drooping in the future. 

Straightened awning looking beautiful

 I am still hopeful of being being able able to negotiate an acceptable outcome to the “blue marks on the ply” problem. To avoid any miscommunication and to try and get something happening faster I am now dealing with the distributor, Gunnersons, rather than the local retail supplier I got the ply from. While we resolve this issue it seems we will get on with building the rest of the house and have to leave the main kitchen/living room, bathrooms, laundry and entry unfinished until I can get a product I can use for a ceiling.

Using Magnesium Oxide Board

Unable to finish the ceilings, while we wait to try and exchange the plywood, we started on the magnesium oxide board internal walls. We chose to use the magnesium oxide board (MgO board) as it is breathable and therefore compatible with the hemp walls, but it is also fire proof, mould proof, rot proof. MgO board in a relatively new product in Australia, it is all made in China. Price wise it is cheaper than fibro but more expensive than plasterboard. I researched the Internet for fixing and cutting methods. It was recommended that the MgO board be cut with a jigsaw or a low speed circular saw. I have a circular saw but it is only a high speed one and I did not want to blunt the blade and did not use it. The other option is to score and snap the board but I was not confident that this would give a neat join with an 8mm board. So I used my jigsaw. I quickly blunted the first blade but did not take notice of how sharp the blade was in the first place, so I changed the blade. After two or three cuts the new blade was also blunt. I went to the local hardware store to get a fibre cement blade, as I had been using wood blades, only to find out the no such blade exists. I queried how people cut fibre cement sheets and was shown a tool that looked a bit like a pair of bolt cutters. These would never work on the 8mm MgO sheets. The alternative suggestion was an angle grinder with a masonry blade.

I tried cutting the MgO boards with the angle grinder. it worked well and was easy to get a nice straight line. It was dustier than the jigsaw, but the masonry blade was still going well after more than 20 cuts. The dust is supposed to be non toxic, but any dust is bad, so I made sure I used eye protection and a dust mask when cutting the boards. Cutting the boards was straightforward and not difficult. I set up a large flat area with a couple of movable spare OSB boards, reused from the formwork, so I could make a gap where I needed to cut and leave the remainder of the board supported. This worked well.

The MgO boards are fixed with screws and the boards can be laid vertically or horizontally, depending on the wall dimensions. Vertical joints should be on studs and fixed each 200mm on edges and 300mm centres on intermediate studs. However the instructions also state that the boards should not be fixed with in 60mm of corners, presumably so the corners do not crack off. Also the edge fixings need to be 12mm from the edge, presumable also to prevent cracking. With 40mm wide studs this allowed just enough room to join the boards on a stud. The boards were tapered at the edges so if you were painting them you could tape and fill the joins. As I am rendering the internal walls, so they look the same as the external walls, I am not doing this, but will use a render mesh.

Cut sheet of MgO board installed

Several sheets of MgO board put up

I went to a large chain hardware store looking for fibre cement screws, they have a different tip and cutting barbs under the countersunk head. The hardware store did not have any fibre cement screws so I bought a packet of galvanised timber screws that looked like they had some barbs under the countersunk head. The timber screws worked but were a pain to put in, and were slow, you had to push really hard to get the countersunk heads to go flush without shredding the Phillips head in the screws.

A week later I sourced a box of 1,000 30mm galvanised fibre cement screws with square heads from Nepean Boltmaster.  These were great, went in easy, no chance of shredding the thread. Fibre cement screws were recommended and they definitely make the job easier.

Timber screw in left, fibre cement screw on right

I was one bag of insulation short to finish the house, plus I had not bought insulation for the hallway. I bought the sheep's wool directly form Higgins Insulation and picked it up from their Villawood warehouse to save transport costs. When I complained about one bag of insulation being a batt short and one bag being misshapen, I was advised that their Sydney operation had closed down. Then when I called head office in Queensland I found out that although the Sydney operation had the same "Higgins" name it was separately owned, this meant that I could not do anything about my missing batt and if I wanted to finish the house in sheep's wool I would have to get it from Queensland. If I was going to get one extra bag of insulation, I decided that I might as well do the thinner raftered hallway in sheep's wool insulation as well.

Four not five batts

Misshapen batts, correct batt in the centre

I ordered three bags of R3.0 580 x 1200mm batts. Higgins in Queensland gave me a quote for transport and the first quote was higher than the cost of the insulation. They could see that was ridiculous, so made other enquiries about transport. The next quote was better and less than half the cost of the previous and was half as much again if I collected it from the transport company depot at Wetherill Park. So I collected it from Wetherill Park.

I had put some packs of insulation in the car before and thought I could fit three packs in, but the packs I had collected before were smaller and these were packs of 6 580 x 1200 batts.  I had the family with me as we stopped to pick up the insulation on the way down to Culburra. The lady at the transport company thought there was no way we could fit it all in and my family berated me for not bringing the trailer. So everything was emptied out of the car, my son's seat was moved to one side, and we fitted two packs of batts in the boot and one behind the passengers seat and the rest of our gear was stuffed in around the insulation. We were fortunate I could fit it all in, but lesson learnt when picking up insulation.

Once we had the insulation it was not a problem finishing the installation although one section where the front pavilion joins the main pavilion and all the water and gas pipes were was a little tricky and the insulation had to be slit and tucked around the pipes. The whole house in now insulated and it does make a noticeable difference to the temperature at night.

Work also continued on finding the right render colour. Our earlier render tests showed us that we would need to use some kind of cement colouring oxide to achieve the colour we were after. I went to South Coast Decorative Concrete Supplies hoping to get several different oxides to try out however they only sold the oxides in 9kg bags, which made it too expensive for me to get more than one bag. After much debate I chose Sundance from Concrete Colour Systems.

CCS Sundance oxide

I mixed up small batches of render using 1/20th of a bag of render mix and then divided this in half, making up a mix using 1%, 2% , 3% and 4% oxide. However I only had kitchen scales accurate to 1g to measure out the oxide and I was using such a small amount of oxide I was hard to get it accurate. I have since ordered a set of jewellery scales on E-bay that are accurate to 0.01g.

1% and 2% Sundance oxide when still wet next to the earlier render tests

I chose the Sundance colour as it had an orange tinge to it which I though would counteract the greenish tinge of the uncoloured render. However, the Sundance looked a bit more orange brown than we wanted. We are looking for a light warm yellow. So we bought a 500g jar of Yellow Builders brand oxide from the hardware store. That turned out way too yellow an still has a slight greenish tinge while wet. We then tried the 750g jar of Sandstone Builders brand oxide, although we have not yet seen it dry the test when wet looked too brown. The closest to the colour we wanted was the 2% Sundance so we did a further test of this on the hemp wall and on the MgO Board and will see how this looks when dry. The more accurate scales will allow us to do more accurate tests in the future.

Top row 4%, 3%, 1% and 2% Sundance all dry. Bottom row on MgO Board 2% Sundance, 2% and 1% Sandstone all wet

2% Yellow and 1% Sandstone both still wet in afternoon sunlight

2% Sandstone and 1% Yellow both still wet photographed with flash

Work has now stopped while we wait for the" blue marks on the plywood" situation. We hope to get building again soon.