Category: Earth Tubes

This morning, we tied our pulling ropes to the 6 support struts and mortared
the cement board down on top of the wooden T supports.

Cement-board-mortared-in-place

We are letting it set and cure before we screw the cement board down and
start filling in the whole area with the sandy soil, hardcore rubble and
everything else that is rubbish to compact it down solid and rebuild up the
level back up to the foundation point.

Today, while we waited for the delivery of our 300metres of the 20mm black
plastic pipe to come, we worked on finishing off the Earth Tube Mixing
Chamber and the Air Tunnel structures.

We dug around the whole chamber and tunnel, removing a spade width of soil,
down to the foundation slab. This is to allow for us to insert a layer of
DPM plastic sheeting all over the concrete blockwork plus a sticking out piece of
about 100mm as well. All this is to keep the whole unit dry and keep our air
supply from getting damp with wet weather.

Next, we got a large piece of cement board, 10mm thick stuff, and placed it
on top of the remaining part of the tunnel that goes under the main house
foundation, and cut it down to size, with a triangular notch cut out to make
a 300mm square “hole”.

Cement-board-mortared-in-place

This cement board needs lots of extra support inside the tunnel as it is
going to have to take the load of ready-mixed concrete being poured on top.
We wanted to make sure that the weight of the fluid concrete will NOT
suddenly snap the lid! We tested the strength of the cement board by putting
a medium sized piece 150mm apart on two bricks, and put more and more load
on the middle and find out if broke or not. It survived Stephen’s weight of
80kg at the end!! We tried separating the spacing to 250mm and worked our
way up with the extra load but it snapped with my weight of 70kg. This led
us to conclude that a spacing of 180mm would be just fine and we can have
enough to fully support the whole board.

So we made six T shaped wooden module with one horizontal strut and one leg.

Cement-board-supports-1

Cement-board-supports-2

Each piece of wood will have a length of string tied to them, ready for the
final process of removing this support mechanism.

Tomorrow, we will seat the cement board on fresh mortar on the edges of the
tunnel and press down to firmly hold the support struts into place. Once the
concrete is poured and set, we can pull on the twelve ropes to yank out the
individual pieces of the support modules!! We hope we can rescue the pieces,
all 22 of them!!

The-strings-to-remove-the-supports

During a long session, starting this morning at 10am, we assembled and
mortared all the pieces of the air tunnel together and finished about 2:30pm
with the lids going on!

We needed to mix two loads of mortar as we just ran out at the point of
having done the two rows of the walls. So all the remaining mortar, after
finished cementing down the concrete blocks on as lids, we spread it out all over the
whole Earth Tube Mixing Chamber and down the slope of the air tunnel to seal
and cover up the joints.

Earth-Tube-Tunell-Mortered-Together-2

Earth-Tube-Tunell-Mortered-Together-1

We will now let that all set for a couple of days to harden, then start
chucking in all the remaining hardcore and sandy soil around the area to
build up the levels again, ready for the foundation!

In the meantime, we start doing the Energy Modules!!

Today, it was the day of slicing many concrete blocks to create the air
tunnel from the Earth Tubes Mixing Chamber to the house! The jigsaw puzzle
was very complex with a three dimensional aspect to it, both sloping
downwards, curving around and also widening out too!!

There was at least 17 cuts made, using a 9inch diamond disc in a high
powered angle grinder machine.

Erth-tube-tunnel-blocks-cut-to-fit-1

Erth-tube-tunnel-blocks-cut-to-fit-2

Erth-tube-tunnel-blocks-cut-to-fit-3

We need to go and buy two more concrete blocks to complete the “lid” to the
tunnel. That’s tomorrow’s job along with mortaring all the pieces together
into one smooth solid unit!

After we have finished the sewage pipes (the filling in of their trenches),
we started with the adjustment to the Earth Tube Mixing Chamber and the Air
Supply Tunnel construction.

The foundation slab is all set and very nicely done!

Earth-tube-Concrete-finished

We managed to get the end segment off the chamber with only having to
destroy one of the concrete blocks. Now we are planning the procedure of
what blocks to go where and what angles to slice certain blocks to form the
downward slope of the tunnel exiting from the mixing chamber etc. etc.

On Monday, we will resume and finish this task and then fill in all the soil
and the remaining hardcore material back in around the chamber and tunnel
and compact it all to build it up to the required level for the main house’s
foundation etc.

This morning, we mixed up 3 bags of cement and 18 buckets of ballast and
poured the lot into the open area we had all stuttered and ready. This slab
will form the base for building the tunnel from the Earth Tube Mixing
Chamber to connect to the house, thus bringing in fresh air from under the
garage via the collection of large 6inch diameter tubes!

Earth-Tube-Tunnel-Concrete-laid

After lunch, we will smooth it off and cover with plastic sheeting to keep
it moist against the hot Sun and dry weather we got at the moment.

Today, while we waited for the building control inspector to visit us, we
got on with making adjustments to the Earth Tube Mixing Chamber. We had
originally constructed it several years ago and since then we had shifted
the whole house position 300mm closer to the Loke and also put it 100mm
deeper too! This meant that the chamber, constructed with solid concrete
blocks (430mm by 215mm by 100mm wide) was slightly out of position and we
decided to adjust the design of the chamber. Instead of the connecting
“Tunnel” coming out the side like a letter T, we have moved the connecting
tunnel to the end of the chamber, and will have it sweeping around and
coming into the correct position from the Loke side of the house, underneath
the main house foundation. We have it sloping down and curving around to
fully go under the 150mm thick foundation strip and arrive exactly in the
corner of the utility room.

All this is for our fresh air supply for the house, the concrete tunnel
measures 450 high by 250mm wide to allow the maximum flow of air with
minimal resistance.

Today’s job was to dig dirt and soil out for the route and insert in shuttering to form the foundation slab to build the tunnel upon.

Earthtube-tunnel-foundation-shuttering

Tomorrow, we will make up a quantity of strong concrete and pour it in and
while that is setting, we can get on with filling the sewage trenches.

Where the earth tubes get close to the house we have built a block work chamber to concentrate the air flow down too a smaller tunnel to pass under the foundations of the house. The chamber is 300mm below the path round the house.