Hemping timber lintels and up to ceiling height

Joined by our good friend Steve, who had travelled down for the weekend from Port Macquarie, we managed a day and a half of hemping over the weekend. Steve had helped us bag the inside of our mudbrick house almost 10 years ago and had helped friends build a straw bale house earlier this year (http://www.pearlandelspeth.blogspot.com.au), so he took to hemp building quickly.

Friday we started a new wall on the western end of the main pavilion. Hemping without the interruption of noggins and windows was a breeze and we clocked up 9 mixes in the afternoon. Forming up and hemping the acute angle between the main and front pavilions was not difficult.

Acute angle between pavilions

 Saturday morning we tackled the difficult spot of hemping up to the ceiling and above the windows.  We were worried about the hemp not having anything to key into above the windows as there was a large timber lintel and the hemp only joined up with the other side for a small section above the top plate. To combat this we improvised some timber v-shapes across the lintel where it was thinner than the frame timbers this would allow the hemp to key around them and the v-shape provided resistance to gravity to stop the whole section of hemp just falling out. On the inside the lintel was flush with the frame timbers so we added a cross piece to our v-shaped timbers, with some added holes in the cross piece for more keying in. All of the timbers were at least a finger width inside the form work to allow coverage by the hemp and to allow them to be easily packed around. The timber pieces were easy to hemp around and when the form work was removed there was no apparent movement of the hemp. We did however leave in place the form work on the underside of the top of the window and will do so until just before the windows are installed.

V-Timbers on the outside of the lintel

V-Timbers on the inside of the lintel

Form work away from v-timbers

Working high up was not as difficult as we expected, the secret to this was keeping the rises small - about the depth of your hand. As the join between rises is an area then can be a bit weak we raised the outside form work to its maximum height, but raised the inside form work up in two stages. As soon as we had hemped to the top of the inside form work and hilled the hemp up against the higher outside formwork we removed it and raised it up. It was not a problem moving the formwork up so quickly as the boards were large enough to completely support the work that had just been done and this quick movement of the formwork prevented there being a joint between the rises. Work was slow and we only got 5 mixes done in a whole morning. 

Hemp done to ceiling

Corner section to ceiling

Outside wall to eave line

Hemp above window to eave line

To take a break from working high up we spent the afternoon doing the second rise on the western wall of the main pavilion and the hall way. This was so much easier and we got a further 13 mixes done - more than making up for the slow morning.

Western wall of main pavilion

Around the corner into the front pavilion

Progress on the hallway

Just to prove that it is not too early to swim at the beach in mid September we all jumped in for a dip before the trip home. The south coast water felt icy, at least until I lost the feeling in my feet.
   

Hemp Building Video and meeting other hemp builders

With help on site over the last two weekends we have been able to film a little bit of the hemp building process.

As we have got closer to the roof our rises have had to get smaller, as your arm reach gets smaller when you are building at almost head height. The invention of the micro tamper, with a handle as long as your fist helped save the day. It joins the wide and narrow full size tampers, the half sized mini tamper, the L-shaped tamper, and the no handled tamper as well as various sizes of timber (for narrow spots) as pasrt of our array of tamping implements. Further difficulties have also become apparant such as how to get the hemp mix to stay against the lintels where there is very little space for it to key into the other side. We will try our solution to this issue next weekend.

Tampers - Wide, Narrow, Mini, Micro and L-Shaped

Difficult section at lintel above window

It was with great joy on Saturday that we started hemping the main pavilion of the house (the house being in three pavilion like sections) and shared this with Nicole, another hemp builder from the south coast, who will commence building her hemp and stone walled studio soon. Nicole shared with us the progress of her build, including the ease with which she got Council Approval, compared to the difficulties I had, despite us building in neighbouring Council areas. Hopefully we will be able to continue to share hemp building knowledge and resources. After working on the higher sections of the walls working back at ground height was refreshingly easy.

Tamping the first rise in the main pavilion

First rise in the hall and main pavilion

View of the future courtyard garden

 With the formwork stripped off we could see how much we have done. We have done 132 mixes to date over 4 weekends, which I estimate means we are 1/4 of the way through the walls. Another milestone is that we have used one of our five pallets of binder. To get the hemp out of the way of the walls so that we can build them, we have been using about half a bale of hemp until they are light enought to lift ontop of each other. With a bit of manouvering we now have access to all the walls so that the plumber can finish roughing in all the pipes. The plumber was not able to do this earlier with all the bales of hemp in the way. I had been planning to do the kitchen wall next until I realised the gas and water pipes had not been properly finished off. Instead we hemped the back wall of the main pavilion, until I realised I could not go more than one course high as the pipes had not been put in for the instantaneous hot water system. We can not go much higher on the back pavilion until I get the awnings put up as they attach to the frame. Hopefully I will be picking the steel connector plates, for the awning, up from the metal fabricator this week, so this work can get under way.

Walls finished to lintel height

Back wall of the back pavilion

Inside one of the bedrooms

Back pavilion and hall with expansion joint between

We also saw four seals this weekend

Help arrives at hemp building

On the last day of winter we began to share our hemp building skills. Tony, who we had met at Klara Marosszeky's Hemp Building Workshop in October 2011, joined us for the weekend. Braving an afternoon cold front that significantly dropped the temperature the three of us managed to do 18 mixes of hemp walling, working in some tricky areas under the noggins.

Saturday brought improved weather and further reinforcements, friends Martin and Nerida and Tony's son, Joel and Joel's partner, Alice. Our helpers picked up the mixing and tamping skills quickly and did a great job. As the walls got higher we used firstly milk crates and a plank as our scaffold and then a plank on a some steel stands. To fill and tamp the walls as they got higher we had to be able to both see down into the form work and be able to reach a hand or tamper down to even out and tamp the layers of hemp lime mix.

Hemping higher up the walls

Working in a section with several closely spaced studs

Once again we were working under window sills and noggins, but changes to the placement of form work made the work easier. The form work was at or just below the sill or noggin on the outside and about 12cm below the sill or noggin on the inside. This created enough room for an arm to reach under the noggin, but also allowed the hemp to be built up to and under the noggin on the outer side with the inside to be filled when the form work is moved up. Work was slow where there were lots of closely spaced studs, but difficult to get at sections were easier with one person spreading and tamping the hemp lime mix from the outside and another working from the inside.

Tamping under a window sill

Window sill - sloped down on the outside to shed water

There was great camaraderie and we set a new daily record of 26 mixes, bringing our overall total to date to 102 mixes. To achieve this we had five people working all day and extra two people for half a day, however when we had seven people two were moving form work up while the rest mixed and tamped the hemp. We have been using half a bale of hemp until it became light enough to lift on top of the other bales of hemp, this is so we could clear more floor space and gain access to more of the external walls so that we can form them up.

Layers of hemp - differing heights of layers due to location of noggins and windows

Layers of hemp finished over different weekends

Sunday was a glorious sunny spring day and this made the work of moving the form work up more pleasant, as did working with a tall helper. As the form work was moved higher up it became necessary to have two people to move it up. In one section the form work has been moved up to where it will join the eaves lining, we will probably have to do this section in small rises, with the form work lower on the inside.

Form work getting higher

Form work moved up, one section on outside to eves height