We haven't quite finished wall-raising, but we have started on the wall plate and this week is going to be mostly about this phase of the build. The wall plate is a ring beam that sits on top of the final course of straw.
And we spent a small part of the day on the wall plate. We glued and screwed the outer beams to the OSB bases. The wall plate is going to be in six sections, and each section is likely to be so heavy and awkward that it will take three of us to carry it. .
When we had it laid out on the ground on Friday, we marked up the exact location of each piece. So today, we were glueing one side of the beams, locating them on the OSB and clamping them, and then turning the assembly over and drilling then screwing through the OSB to pull the glued surfaces into tight contact.
Six wall plate sections laid out. I have positioned the inner beams, and marked them up for fixing tomorrow.
But most of today was spent completing the fourth course of bales. These have been in place since Wednesday, but before starting the fifth course we have checked and adjusted the position of all bales for alignment then driven 1350mm hazel stakes (two per bale) down through all four courses. It's been a day's work. You can't see the difference in the photographs, but I hope it will make a significant difference to the evenness of the walls at the finish.
Day 2. POOSHers = 3, Weather warm, dry and sunny.
We laid the fifth and final course of bales in a couple of hours this morning. It was the most straight-forward course of the five: no stakes to use, no window openings so fewer bales to customise. Better still, one of the part-bales we made last week was the perfect length to complete a wall section today.
Back to the wall plate this afternoon. We have been gluing and screwing the inner beams and noggins (spacers) to make it as strong and rigid as possible.
If you look very closely at the mid-line of the OSB, you can see that we have also drilled 25mm holes here and there. These are for the final hazel stakes that will be driven down through the wall plate into the top courses of straw.
The wall platee - six finished sections back in the store and ready to put on top of the walls tomorrow.
Day 3. Wednesday. POOSHers = 3, Weather warm & dry
It's time to fit the wall plate, and the forecast is for dry weather. So - covers off...........
.......................sections up the scaffolding..........................
Position very carefully directly above the baseplate. Plumb lines, spirit levels, tape measures............
..................then drive in the small hazel stakes, through holes in the bottom boards.
Whoops! No photo of the lovely sheeps wool insulation . All voids were filled with 100mm thickness, then the wall plate top covers glued and screwed (or ring-nailed) into place.
Ready for compression tomorrow.
and I'm hoping that when the straw either side of the window is compressed, the gap between the top course and the wall plate, over the window, will disappear.
Day 4 Thursday. POOSHers = 3, weather : warm, dry and sunny.
We have pre-compressed the straw today. We have worked our way around the walls with four steel bars and four heavy duty ratchet straps. If you look at the photos in "Wall-raising, Week1", you can see some lengths of blue water pipe running across the stem wall at regular intervals. These were marking some slots I had cut across the stem wall ready for this job. We push out the pipe with the steel rods - 20mm steel rebar cut to 600mm lengths - and pass the ratchet straps from one end of the bar up and over the wall plate then down to the other end. When you tighten the ratchet straps, you compress the straw wall between the base plate below and the wall plate above.
Before moving the straps along the wall one at a time, a length of (white) polyester pallet strap goes over the wall plate and under the base plate, tightened up with a monster parcel strapping tool (hired), and this strap is left in place, permanently. It will be plastered over.
Pictures follow, not necessarily in sequential order:
So: this last photo shows what we have achieved today. We have reduced the height of the walls by around 5 cm! The top of the wall plate was level with the black line on the post before we started.
But, by compressing the walls there has been a much more significant change in the strength and stability of the walls. They feel sturdy and steady enough to build a roof on. However, everyone has been working hard for four days, and we have reached a suitable point to take a break, so today was the last day of work this week.