I am about to pour my footings, up to 950mm deep (mass concrete
required to buttress old house foundations, so no strip footings
allowed). I'm still not sure if vibration is really required. But,
then I came across Lafarge Agilia Trenchflow concrete. Not sure if its
price, but it is described as no vibration required, self-compacting,
can be levelled by one person, virtually self-levelling. Anyone know
about this, and if it sounds like a good idea, since I may be short of
manpower on the day I want to pour.
It is basically 3 sides of a rectangle, total length about 9 metres.
It will be pumped by pipe or boom depending. But definitely not a
I guess the stuff is just super-plasticized concrete.
Well I used this "agilia" self compacting concrete (I had to find
out !). It was pumped in from one location and flowed around all 3
sides. It self-levelled and I did not touch it once, did not tamp it
or do anything. It filled like a bath. If you had normal concrete
wetted this much, it would have lost it's ballast. The concrete pump
guy said it was a dream to pump.
Which left me to sort out the small pile that could not be pumped from
After 24 hours, I scraped off a loose foamy layer on top which was
actually a mixture of air bubbles from the self-compacting process,
some additive from the concrete and the diesel that the pump guy used
as a release agent. Apart from a few localised high spots that I
chipped away, it was surprisingly flat, and more importantly, level.
The only snag was that the level on either side of the shuttering
around the sewer pipe was slightly different (by 30mm), requiring a
different stragegy on each side to get the brick courses at the right
A bit of fiddling with 73mm bricks and concrete blocks will fix that
The concrete was 78 quid per cube (normal lafarge was 70 quid), which
sounds like it may be a little expensive, but it meant I could do the
job easily on my own.
Things I did wrong (may help others):
1. Did not consider that the levels either side of the shuttering may
end up different.
2. Did not insist we filled from 2 locations (possibly avoiding point
3. Allowed the guy to empty his pumping pipe (around 12 metres of 4
inch pipe) into the trench, which took the levels higher that the
height pegs I had in. This means I may have to chip a bit of the
foundation away to get the roddable bottle gullies in close to the
wall at the correct height. No problem for an SDS though.
All said, quite a painless job !