Having worked in the construction/house buidling industry for many years it
was decided that we wanted a masonry shed to store our rolling stock in. While
timber offers speed on construction and potentially better thermal insulation,
it also requires more long term maintenance.
While working for CALA Homes, I went on a factory tour at Durox who make
aerated concrete blocks. While in the factory we were given a demonstration of a
glue system which used oversized blocks which were glued together with a thing
bed mortar. This system provided a weatherproof skin which builders could
assemble at great speed and then go back and cover with bricks.
While it potentially offered time benefits to the house builder, it offered
the advantage of masonry construction with some thermal insulation to the shed
builder. Aerated blocks also have the added advantage of being able to be cut
with a masonry saw or even an old wood saw.
Durox Block thin bed mortar system
Durox blocks are water resistant and can be used on the external face of a
building. Usually they are rendered but for a shed all that is needed is a coat
of masonry paint. Quick, solid and isn't going to rot in 10 years time. Note in
the top picture, use of the train for bringing up the blocks. Saves a lot of
time and manual handling.
As we were un able to obtain the Supasystem (large blocks) we used standard
size blocks. Only difference is the extra glue required.
- 200mm of hardcoare
- Sand blinding then compacted with a wacker plate
- 180mm reinforced concrete
When casting such a large slab it is worth looking at the alternative of
mixing it yourself. A quick look through the Yellow Pages will reveal many
companies which will mix and lay concrete. If you value time and your health -
get the professionals to do it.
||Shed before painting and felt roof. Canopy only existed as we
were too lazy to cut the 3m long joists. Fascia is made of plastic and cut with
a hole cutter and a jigsaw. The engineering bricks have two purposes
- act as a damproof course without weakening the structure.
- Create a level finish for the block sytem to be set on to.
We used brick tor on every 3rd course. Brick tor is a steel wire/mess which
re inforced the joint and helps reduce cracking.
||There are limits to how nuch of the elements you can keep out.
Thames Water pushed it to the limit four times but still blamed it on customers
actions (ie wont pay for damage caused). How many customers put gulley gratings
and broom heads down the sewers??
Oh the joy of a private monopoly.
External finish is Hi Build - a thick textured paint which can be applied
with a float before finishing with a paint roller.
Some simple notes on
- It is wrong to assume the more cement in mortar the better. 1 cement to 6
sand is more than enough strength for most construction purposes. If you make
the mortar too strong and there is any settlement, the bricks or blocks will
break as against simply settleling.
- Garden wall foundations - the deeper you go the better. At least try to go
down a foot or so to clear the vegetation layers, where most of the ground
- Plasticiser additive. This is a mild detergent that makes the sand and
cement more fluid and requiring less water (less staining when you get it on the
face of the brick). For years you would catch brick layers on site adding fairy
liquid. Of course I can't recommend that!!!!
- Mixing concrete and mortar by hand is not easy. Rent a mixer in if you are
going to anything larger than a couple of dozen of brick. If you are careful you
can lay bricks on concrete foundations laid the day before - eg Saturday/Sunday
A standard brick
- Front Face (Stretcher) 65mm tall x 215mm long
- End (Header) 65mm tall x 102.5 width
Sounds funny dimensions but makes sense when you add a 10mm mortar join.
- Height 75mm (3") with one joint
- 2 bricks end on with one joint between = 215mm (length of stretcher face)
- One stretcher face with joint - 9"
Of course bricks are not millimetre perfect but there is a British Standard
on tolerences but if you bricks are slighlty smaller or larger you take up the
difference in the mortar bed joint.
If like us you find brick laying very hard, cheat. Use engineering bricks
which can be cleaned off with a wire brush after the mortor has set. Many face
bricks are ruined if you get mortar on them.
nice leaflet on brick bonds
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