hello I'm Roger Bisby from Skill Builder and I want to talk to you
about some changes that have taken place in the British Standard for tiling this is
the British Standard 5385 and that the changes took place in June 2018 and what
they now say is that basically, tiles are getting heavier so they've revised the
standard to make sure that people are not attaching heavy weight tiles to
unsuitable backgrounds or if they are attaching them they're doing it in the
right way now plus the ball is still the most popular substrate for tiling on to
because it's cheap because it's easy that's what people tend to use now
interestingly if you are tiling in a wet area the British standard also says now
that that area has to be tanked now if you're using plaster board it means
you've got a coat that pass the ball with a tanking membrane you've got to do
the edges because the water can creep up through the edge but even if you're
using moisture resistant pass the ball it still needs to be tanked so the other
important change is that plaster board is capable of taking away this thing to
take away - say 20 kilos per square metre now the British Standard is saying
that your tile if it exceeds 70% of what the substrate will take then it needs to
be continuously bedded that means of not traveling over the whole surface area so
the plaster board will take 20 kilos we've got a towel here which is a 10
millimeter porcelain tile this is coming out at about 18 kilos a square metre so
if you do the maths on that you can see that you haven't got that margin so you
need to make sure that that's continuously bedded with a notched
trowel and press down firmly to do that but bear in mind that that is when the
plaster ball is dry that it is what it's working at its most efficient and it's
still working at the critical edge of its limits so it makes it even more
important that you use good tile backing board now
some people would say okay I use marine ply what's wrong with the using marine
ply well in actual fact the new British standard is also outlawed plywood or any
kind of timber because what they're saying is on the vertical surface the
plywood or the timber is not suitable one thing it can be laminate the other
thing is that it supports mold growth so if any moisture does get in through
those grout lines it very quickly sets up a mold growth which destroys the
adhesive and the grout and so on so that's out Lord we can forget that you
can still use it on floors by the way if you want to but on walls it's an
absolute no-no so everything points towards using a proprietary tile backing
boards such as this elements board and it really is the ideal surface for the
job now interestingly although this is a lightweight ball that you can see that
it's got this foam cell in it it's covered with a polymer adhesive and a
mesh which makes it the ideal surface for tiling onto so much so that this
will take in excess of 60 kilos per square meter now if we look at our tile
we can even go heavier than this which is 80 kilos a square meter but you can
see that we're well within our margin if you can achieve 65% coverage that's
perfectly permissible so working with this board allows you to have that
little bit of margin now I hope that's cleared something up because I know a
lot of people say you could never dot in there you could never do anything but
not trowel through and it all depends on the substrate you're using and it's
important that when you're applying tile adhesive with a notched trowel that you
do it in straight lines because if you use swirls that means the air can get
trapped in the tile adhesive and reduce the contact now interestingly even
though we've used the approved method of applying the tile adhesive with a knotch
trowel and we've even moved the tile slightly sideways to increase contact
you can see here that we still haven't achieved a hundred percent con
act on plasterboard so you can see that on the elements board using the knotch
trow we've achieved what you would save is virtually 100% coverage even though
we don't really need it now looking at this cotton Deb method you can see that
we've achieved over the required 65% okay it's not the most perfect method
but in reality because walls aren't always straight that's what a lot of
Tyler's are having to do there is a difference between what's put down in a
standard and what's actually done on-site so the ideal solution is to use
the tile backerboard to get your wall absolutely a hundred percent flat and
plumb so that if you're tiling you can go on with the minimum of adhesive and
produce a good content so interestingly it could be argued that by using a tile
backerboard you're actually saving on adhesive so
what have we learned here well we've learned that it's in the preparation and
by using the tile backerboard we can actually achieve the british standard a
lot more easily