Finishing the roundhouse roof rebuild at Boiling Wells!

Today, the last of the sedum mat was fitted onto the roof of the roundhouse. Hurray!!

The terracing timbers still look very new, but hopefully their appearance will mellow at the same time as the sedum grows over them, so that eventually the whole roof will look more 'organic'. The terraces seem to have helped solve the problems of the ridiculously steep pitch that the roof has in places. The roof also doesn't look too regular and symmetrical because the timber frame isn't, which I like.

There are three different kinds of sedum in the mat. Here's a picture of some of it:

We left sedum off the compartments just below the windows, as rainwater running off them would probably wash away any growing medium and plants during heavy rains. Hopefully the gravel will baffle such water flow a bit.

Now to get on with the next bits to be done: sorting out the cordwood wall and fitting doors.

The cordwood wall was put in unseasoned. As it has seasoned the wood has, of course, shrunk so that some of the pieces can now be pulled out of the wall completely. A lot of it is also ash and plum, both timbers which woodworm is very partial to.

I'm planning on spraying the wood with borax solution to deter worm attack and then lime rendering around the pieces. It may take a while, but it will sort out the shrinkage problem and I prefer the look of the lime render to the cob, to be honest. Lime render is also tougher than cob, which can be scratched away with a fingernail in places. I'm not sure when it will be done, as a lot depends on funding and  the number of helpers available.

Watch this blog to see how things go...

Fitting a new window in the roundhouse's cordwood wall

There has been a bit of a break in fixing the roundhouse roof, thanks to some heavy snowfall (a note to readers in Canada, Scandinavia and other areas used to snow- more than a couple of inches (5cm) of snow in the UK and everything comes to a grinding halt).

(No, really!)

In the meantime, we decided to fix the window which was broken by the weight of the overladen roof pressing down on it. See the post at http://carvingswithstories.blogspot.co.uk/2013/01/fixing-boiling-wells-roundhouse-roof.html for the full story...

 Anna and I, together with the young people that are volunteering through their schools to help on the project, assembled a new window in the Boiling Wells barn last Tuesday.

The previous day I had collected together some offcuts of  European Larch from my workshop and routed a groove along each one to take the replacement toughened glass double glazed unit, which had arrived at the farm site. The volunteers and I then cut simple mortice and tenon joints to join them together . The assembled frame was finished with linseed oil and left to dry.We also had enough time to make pizzas and cook them in the wood-fired pizza oven. Yum!

When assembled, the frame looked great!

Today, Simon and I fitted the window into the roundhouse wall. It was a bigger job than it sounds!

The previous window was a glazing unit slid into slots cut in the surrounding cordwood logs. There was a lintel made of three sweet chestnut sticks, the central one of which was also grooved to take the top of the glazing. The adjacent, surviving window was put together in a similar way, which you can see below.

To fit the new window, we needed to brace up the sweet chestnut stick lintel, as it supported the cordwood wall above. We then had to the rip out the surrounding notched logs (many of which were nailed to nearby posts) in order to make room for the new frame. The wall underneath also needed to be partially rebuilt, to give a level surface for the window frame to sit on.

We put in a temporary brace, then inserted two sweet chestnut poles to make new lintel bearers. We also thought that leaving the old lintels in would give more support to the wall above and protect the new window from going the same way as the old one...

We could then fit the new window, using builder's metal strap to attach it to surrounding logs and posts securely.

Cheese!

Finally, we mashed some of the removed dried cob with water to make it reusable and started to fill gaps around the new window with a central straw insulating core and cob on the outer sides. 

 

We need to finish putting the cob on (nightfall stopped work) but the new window looks great! To be honest, we all prefer it to the one slotted into the logs. The contrast between the straight lines of the frame and the cordwood wall looks better and less slapdash than the previous window. It is also easier to remove and replace the window if needed (important in a community-used space).

 I'm quite tempted to put a couple of layers of lime render over the cob in the cordwood wall eventually, as it looks neater in my view (although the metal builder's strap may need to be protected from the corrosive lime mix). It will also fill some of the gaps left by the unseasoned logs originally used, which have shrunk as they seasoned. Some can now be pulled out of the wall completely. 

The logs should also really have been debarked before being used in the original build but time was tight for the Shift Bristol crew who built the roundhouse and so some things couldn't get done.

Before lime rendering, I'd also like to spray a borax solution over the logs in the cordwood walls as a mild insecticide. Some of the cordwood logs used are from fruit trees such as plum, which will probably get hammered by woodworm pretty soon if nothing is done to protect them.

So Simon and I had a pretty busy day today! However, the snow did come in useful in one way. Since there were no groups of young people on site, we could keep our incentives to finish the job nice and cold until work was done and we could enjoy them...

Next job, finishing that roof!