Building Between a Rock and a Hard Place

[Sharkey]

I live in the Blue Mountains on the western edge of Sydney. Our house is built on a sloping bush block with lots of rocky outcrops. Just off the back of the house is a small area that sits under a rock overhang. The level area is only about 3 x 4 metres and we have some sandstone crazy paving there. There was a clothes line there until a tree fell and wiped it out. The photo below was taken just as I started lifting the paving that was there - September 2009.



We have always wanted to do some serious landscaping work on this site to make the most of what is a unique and spectacular spot. We decided that a wood fired oven would be just the thing. So we came up with a plan to jack hammer out some of the surrounding rock, lower the entire area and build some proper stairs. This should result in making an area that is 6 x 4 metres ? enough room for a large table and chairs. The pizza oven would be built on a ledge on one end that we would also jack hammer out of solid rock. See the picture below for a very rough guide:



The really difficult part of this build is that there is not even access for a wheel barrow. Everything has to be carried in and out in buckets! Plus when you jack hammer out a cubic metre of rock it occupies about 3 cubic metres of space. On the plus side we have not had to bring in any building materials other than some mortar. The stairs were constructed from rocks that were either dug up or jack hammered out:



Here are the stairs completed in November last year. This gave us the height we needed to excavate the rest of the site to.



These photos are from 2009. I am hoping to pour my hearth slab this coming weekend, just over 12 months after starting. I will put up more photos of the last 12 months, but now that I am finally up to constructing the oven there should be more to discuss.

[fxpose]

Re: Building Between a Rock and a Hard Place

What a cool setting for a wfo! Now that's going to be a fun project.

[Alter ego]

Re: Building Between a Rock and a Hard Place

At least it is all sandstone and not granite!

How have you been breaking it up? by drilling & splitting?

Paul

[Neil2]

Re: Building Between a Rock and a Hard Place

Which way is the prevailing wind ? You won't want to create "The Smoking Pit".

[Eric Pfeifer]

Re: Building Between a Rock and a Hard Place

Looks like a beautiful site!

[Sharkey]

Re: Building Between a Rock and a Hard Place

What a cool setting for a wfo! Now that's going to be a fun project.

I'm not sure that fun is the right word, but I do enjoy a challenge and I'm not afraid of a bit of hard work. The good thing is, there is no deadline to have it finished.

At least it is all sandstone and not granite!

How have you been breaking it up? by drilling & splitting?

Yes, all sandstone. I have been using an electric jack hammer that I borrow from my brother (and my brother) to break up the rock. Some of the sandstone comes out in good size chunks and some of it just powders and it takes hours to get anywhere.

Which way is the prevailing wind ? You won't want to create "The Smoking Pit".

I should be able to get the top of the chimney above the rock. I need to do some clearing up there so I don't start a fire.

Looks like a beautiful site!

It is. That's why I want to create something that I can share with family and friends.

Plus there is a convenient wood pile near by.

[Sharkey]

Re: Building Between a Rock and a Hard Place

Because everything has to be carried out by hand I tried to use a lot of the rock and fill close by. A rock retaining wall was built under the house so the area could be levelled right up to the edge of the house.



Plus we built some gardens - dry stone walls and the fill from the site mixed with chicken manure and mulch. We have also built some raised garden beds on the grassy area at the bottom of this picture in which we have planted pizza ingredients ? tomatoes, basil, oregano, chillies, rocket etc. We like the idea of having fresh ingredients close by.



This photo gives an idea of how much of the rock went into these gardens. It also shows how close the area is to the house.



Here is the bench that the oven will sit on. It sits up against the left wall so most of it will be on solid rock. A lot more rock came out of here than I was originally thinking. I could have built a smaller oven but didn?t see the point of going to all this effort and then compromising on the oven. It was only an extra weekend on the jackhammer to make the space for a 42?. Hearth slab should be poured (hand mixed of course) this weekend.



Interestingly we finished jack hammering on the anniversary of the day we started work ? 19th September. In the next instalment I finally get into some construction.

Sharkey

[Neil2]

Re: Building Between a Rock and a Hard Place

A slab that is part on fill and part on rock should be well reinforced.

[Sharkey]

Re: Building Between a Rock and a Hard Place

Finally I finished my 12 month hard labour sentence breaking rock and construction has begun. The block wall has gone in to lay the slab on and I have started filling in the gaps and crevices. I plan to build a solid rock wall enclosure around the oven. The bench to the right of the oven will eventually be at the height of the cooking floor.



This wall is built from large rocks and fills in the gap under this rock ledge. The wall will continue along in front of the block wall and also cover the front edge of the slab and provide a landing in front of the oven. Again, all the rock for this was excavated from the site.



I really feel I am making some progress now and even heard my wife telling some friends we will be cooking pizza for Christmas.

[Sharkey]

Re: Building Between a Rock and a Hard Place

Of course the weekend I plan to pour the hearth slab is the wettest weekend we have had for months so during a short break in the rain I hung a tarpaulin from the rocks out to some trees. I think it will stay while I build the oven.

On Saturday we cut the re-bar and tied it together, adding a bit extra where the slab is not on solid rock. Then we put in the form work. We drilled some holes in the rock and just used some special rock bolts to attach it. I hadn?t seen these bolts before but they worked brilliantly.

On Sunday we finished off the prep and then started hand mixing the concrete. It was a real family project. My brother, my father, my son and I worked like a well oiled machine. We just did 3 bags (60kg ? 130lb) at a time. For the first load we added a little water at a time and measured how much water was required. We then marked that amount on the bucket and added the same amount with each subsequent load. When it was mixed 3 of us lifted the entire wheel barrow and my son, who was standing up top, emptied and spread.

The entire job from opening the first bag of concrete to cleaning up was completed in less than 2 hours!

In this photo you can see the tarp, the slab and the pile of rocks that need to be built into rock walls.



And here is a close up of the slab. As you can see there was not a lot of form work required. The board leaning across it to catch drips from the rock overhead. I have also found most of the rocks to fill in the cracks and gaps, but they are just sitting in place waiting to be concreted in.



Now I need to buy bricks, insulation, mortar etc ? basically everything for a wood fired oven.

[Sharkey]

Re: Building Between a Rock and a Hard Place

It?s been a while since I last posted on my progress. I had a forced break from construction for a few months so obviously no pizza by Christmas. I finally organised all the materials from Field Furnace early in the new year and started on construction of the oven. I laid the first chain (no soldier course) and cut the floor bricks to fit.

The way the Field Furnace guys build the inner arch is to cut each arch brick so that the inside is part of the dome and the top edge is the right slope for a dome brick to sit on. This makes cutting the arch bricks quite tricky, but there are a lot less issues with the dome / arch interface. Here you can see the arch bricks have been cut and are ready to go in. The second chain is underway.



Here is the completed arch and the third chain underway.



The next day I removed the arch form and was very pleased the arch didn?t collapse. We also completed up to the sixth chain.

You can also see I have started my rock enclosure. The rock wall to the back left would have been too awkward to build after the oven was in place, so it was done first.



And here is a closer shot during the sixth chain being laid. You can see the arch bricks get deeper to be part of the dome structure as you climb up the arch.



I am hoping to get the time to complete the oven over the next month or so.

[mklingles]

Re: Building Between a Rock and a Hard Place

First your build looks great! What a location.

I don't know how dry your area is, but do you have a plan to keep rain water from running down and soaking into your insulation under the oven?

[GianniFocaccia]

Re: Building Between a Rock and a Hard Place

Wow. Nice progress on your oven and I love your inner arch geometry. It won't be long now. Such a dramatic setting for an oven!

[Sharkey]

Re: Building Between a Rock and a Hard Place

First your build looks great! What a location.

I don't know how dry your area is, but do you have a plan to keep rain water from running down and soaking into your insulation under the oven?

Thanks.

I plan to enclose the oven within rock walls. I will mount a gutter to the back wall to catch any water that runs down the rock face and also slope the roof to the gutter.

[Sharkey]

Re: Building Between a Rock and a Hard Place

Wow. Nice progress on your oven and I love your inner arch geometry. It won't be long now. Such a dramatic setting for an oven!

It takes a bit of work to shape the arch this way. I sat the arch bricks in place and marked them with my dome tool. Basically the inner edge of each arch brick is part of the dome and the angle on top of the brick is the angle of the dome bricks at that height. Below you can see the dome is nearly to the top of the arch and it is a simple cut to shape the dome bricks to span the arch.






It was more work up-front but I didn't have any of the issues that many builders seem to have with the transition from dome to arch. I certainly didn't have any of the complicated cutting that seems to be the norm and it is also easier to maintain the round shape. The transition is also relatively smooth. Well, it would be except for the fact I am cutting all my bricks with a handsaw and angle grinder.





This weekend I managed to finish the dome . I will put some pics up in the next couple of days.