On 9 Aug 2006 20:24:19 -0700, Weatherlawyer wrote:

wrote:

The existing bricks (located between the foundations and the newly laid
engineering bricks) are slightly damp; so, I've opted for a 5:1 mix
plus a waterproofer.
Now, 2 days after laying the first 3 rows, the mortar used for the
engineering bricks still appears to be slightly damp and rather weak.

With it being slightly damp I'd say you have to find the reason for the
damp. I would have thought the problem with the masonry was that the
mix had dried too quickly in the ho weather.

Bricks -even engineering bricks, can absorb a lot of water and in hot
weather will suck a mortar dry too quickly.

5:1 using portland cement, is a strong mix. Most use 6:1 but you can
use 8 to one. The idea is to keep the bricks apart as muchas to bind
them together.


On the topic of weak mortar mixes. I recently decided to repair
one of the walls of my standalone, block-built garage. Towards
the base of the wall, the mortar was quite robust and in good
condition. As I looked higher up the wall, I noticed that the
mortar gradually changed colour and became a lot more friable.
The mortar between the top couple of rows of block was so weak that
I could remove it by brushing it with a normal stiffness paint brush.
(I stopped before I removed too much :-)

My theory was that whoever built the garage 20+ years ago ran short of
cement and mixed each bucketful weaker and weaker as he went up the wall.

At least now the wall has an outer coating of strong mortar. I can't
say how long it will last - hopefully it won't fail before I sell
the house!

Pete

--
.................................................. .........................
.. never trust a man who, when left alone ...... Pete Lynch .
.. in a room with a tea cosy ...... Marlow, England .
.. doesn't try it on (Billy Connolly) .....................................