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- Setting out is probably the most important part of any
project. In order to make sure a structure is set at the right angles, use
wooden pegs or stakes and string lines when marking boundaries. If the building is to have 90°
angles then the diagonal measurements would be of equal length. If they're
not, then some adjustment is required.
- Using a large tri square is often
useful. These are available to buy, but you can make your own by nailing
together 3 pieces of slate lath or similar in the proportions
according to Pythagoras to make up a right angled triangle. The proportions are in the
ratio of 3:4:5 if you don't already know. So a 3 ft, 4 ft and 5 ft
pieces would produce a large triangle. Once this has been made, check for
trueness by placing the triangle base on a flat surface and drawing a chalk
line against the upright side. Reverse the tri square and draw another line
which should be parallel.
- Use taught string lines where
possible leaving a 2mm gap between line and brickwork ensuring also that no
mortar sticks to the string line and that the 2mm gap is always constant. Keep checking your work with a good
quality spirit level made by Stabila or similar. Buying a cheap spirit level
could cost you dearly depending on the project.
- I came across a very good tool at
www.bricky.com which I tried out myself
on a building project. I found it excellent for building the internal block
work. The downside of this tool is that you can't use it to match up to
existing external brickwork as the thickness of the mortar bed is set at
10mm. Apart from that, it's pretty good as it contains it's own spirit level
and wastes virtually no mortar.
- Cutting Thermalite blocks is best
done using an old panel saw that isn't quite good enough for cutting wood.
Most joiners throw away saws that most people would keep using much longer.
Ask any joiners you know to save these for you.
- Use a plasticiser when mixing
mortar as this makes the mortar more pliable. A good general mortar should
be about 4 parts building sand to 1 part cement. If you don't have a
mechanical mixer, then mixing small quantities with a shovel is OK. The
method for this is to use a banker board which is board large enough
to mix on. A plastic sheet placed under the board and stretched out to cover
the surrounding ground is a good idea. The sand and cement should be mixed 3
times when dry and 3 times when wet after forming a ring with the dry mix to
hold the water (and plasticiser). 5 litres of plasticiser will be enough per
ton of sand. Washing up liquid is sometimes used as a plasticiser but be
careful of using too much as washing up liquid destroys cement and weakens
the mix.
- If you're using a mechanical mixer
such as a Belle "half bag mixer", you may not be surprised to know where the name
came from. In the old days , cement came in 50Kg bags. Half a
bag of cement was put in the mixer and then filled to capacity with the sand
producing an approximate 4:1 mortar mix.
- Information on digging out for
foundations can be found in the concrete section.
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