[Cob] Bathroom and kitchen

[jane at kirstinelund.dk]

About bathroom floor/plaster:

We are doing our bathroom floor in bricks mortared with clay - a solution
we have tried elsewhere in our community, and which works very well. For
this solution there are several important things to remember:

- Use only hard burned bricks suitable for outdoor use. Else the flor will
be worn down very quickly. Apart from that you can easily use a mixture of
bricks with different colours.

- The mortar needs more sand than the cob mixture or it will crack. We use
three times as much sand for mortar than we use for our cob mixture.

- Use some sort of fibre in the mortar used in the joints between the
bricks. Straw is too coarse for this, but we have succesfully used horse
manure, which is essentially half processed straw.

- Let the floor dry completely, which might take a couple of months in a
moist climate, before treating it.

- Do not use plain linseed oil for treating the floor, unless you can wait
a couple of years for it to dry. We use linseed varnish, but Tonkin Laquer
made from tung oil is probably just as good or even better. The first time
you treat the floor it needs a LOT of varnish. Later you should ad varnish
once or twice a year, but then the bricks are saturated and needs only a
little coating.

If someone needs more detailed instruction in how to make a brick floor,
please write to me.

As for the bathroom / kitchen plaster the solution we have tried untill
now is good quality lime plaster coated with tung oil and then painted
with a painting based in linseed varnish. This works very well in a
private bathroom in one of the houses, but in our common house bathroom it
has turned out very badly indeed as we have mould growing in more and more
places.

The reasons are probably many: The house is a 150 year old brick house
with somwhat moist walls, the bathroom faces north, the room is very small
and too many people use it so it is comstantly moist, even with a lot of
ventilation.

So I can recommend the solution for not too small bathrooms in new
well-drained houses, used by relatively few people.