144 homebuilding.co.uk
image: david burtonMortar joints and bonding
A competent brickie should be able to
replicate traditional bonding patterns
in old solid wall construction. But
make sure you tell them first otherwise
standard stretcher bond may be dished
up. The most common solid wall pattern
was Flemish bond with its distinctive
alternating sides and ends of bricks visible
(stretchers and headers). However, it’s no
longer permissible in new construction to
build traditional solid 9 inch walls, since
they need to comply with modern thermal
efficiency targets (Part L of the Building
Regs). Luckily brickies know a useful trick
to get round this restriction. To build a
modern insulated cavity wall so it looks
like a traditional solid wall, alternate bricks
are cut in half and laid so the ends are
visible without bridging the cavity.
Getting the look of the extension right
also means matching the height of the
mortar joints, which in better quality older
buildings can be significantly finer than
today’s standard 10mm. To replicate the
colour and feel of traditional lime mortar
(widely used until the 1930s) the type of
sand can be varied or a colouring additive
used, perhaps with a dash of lime or white
cement. Where you’re using reclaimed
bricks however they will be relatively
porous and should be laid using traditional
lime mortar.
Finally it’s important to match the style
of pointing, so the new mortar joints don’t
visually dominate the wall. Most traditional
pointing styles were either flush with the
wall surface or had a slightly recessed
‘bucket handle’ concave curve.Render
There are a number of traditional styles
of lime render and it’s normally possible
to replicate them on new extensions using
fairly standard sand/cement-based mixes
with a masonry paint finish. Textured
finishes like roughcast and pebbledash
simply have pebbles or chippings added,
and traditional painted ‘stucco’ adorning
many Georgian and early Victoriangarden, or from walls being taken down to
alter your home’s layout. Be aware however
that second-hand bricks tend to be less
robust and have a higher wastage factor,
so you may need to discard around one
in every four. (For more on choosing the
right bricks see page 76.)Stonework
Matching old stonework can be a difficult
task because most local quarries from
which the stone was sourced closed down
years ago. Even if you can locate suitable
supplies of fresh stone, being a natural
product there will always be variations,
making it harder to achieve the same
colour and texture as an original building.
Techniques such as ‘chiselling’ can be
employed to help match the surface
texture, but you also need to consider the
stone size and course heights. Existing
historic stonework will have grown darker
with age, so it may be worth first having it
professionally cleaned. Probably the easiest
type of stone to match is flint, but as with
all masonry of this type it requires skilled
specialists to work it correctly.
The type of stone that your house was
built with will depend on what part of the
country you’re in, and also on the status
of the property. More expensive buildings
used smooth dressed ‘ashlar’ blocks, with
cheaper squared blocks for ordinary
housing or rough rubble stone for poorer
rural cottages. Given the complexity,
the best advice is to first consult a local
stonemason who will know what is
realistically achievable and the likely cost.
One slightly odd quirk encountered in
many Victorian houses with brick walls is
the use of cut stone lintels or decorative
columns to bays and porches. These were
actually often made from artificial ‘Coade
stone’ and can be hard to source, although
local salvage yards are worth a look.CAsesTudy
We used stone
reclaimed from the
original building’s
external wallThe homeowners of
this now characterful
family home took on
the gargantuan task of
restoring and extending a
ramshackle farmhouse in
the Yorkshire Dales. They
were granted permission to
convert an old lean-to into
a new kitchen and utility
and to add a single-storey
extension to the sitting
room over the stream,
which includes an arched
base to allow the stream
to flow below. The walls
were rebuilt in block and
reclaimed stone from an
external wall and the roof
was tiled in slate.