LOFT CONVERSION PROBLEMS WHEN INSTALLING STEEL BEAMS WHEN THE PARTY WALL IS MADE OUT OF TERRACOTTA OR CONCRETE LIGHTWEIGHT BLOCKWORK
Brickwork is the conventional construction method for approximately 80% of UK houses. However, due to budget limitations during construction, some houses built after 1950 were made of cheaper building materials. When designing loft conversions, steel beams are required and installed in the floor and ridge locations to support the added weight from the stairs, new dormer roof, and floor, which tie into the existing structure. Homeowners may lack the experience to identify potential issues when purchasing a house with a party wall that is made of anything other than brickwork. In this article, we will explain the problems that may arise.
Can I build a Loft Conversion if my Party Wall is made from Terracotta or Concrete Lightweight Blocks?
Over the years our design team has experienced all sorts of issues when Homeowners contact us in relation to Loft Conversions.
The most common story we come across is that plans have been drawn up by another inexperienced Architect or Designer where no proper survey has been carried out on the property. We find this out because we carry out our own site survey of the property thoroughly by our experienced team covering accurate dimensions, taking photos,
and examining the building makeup of the construction methods used to build
the house. Our finalized drawings are 99% different compared to the
drawings we are given by the homeowner. Dimensions are out,
drawings are out of scale, and lack detail. Sometimes the roof
heights are out or stairs are drawn in an impossible location to
work. We redesign the scheme to work even in an event where
the Party Wall cannot be used due to weak material being
used. Very rarely the Party Wall is not made out of the usual
9-inch Brickwork but made up of cheap material just to form
a barrier from the neighboring house for fire protection purposes.
Materials used such as Terracotta hollow blocks are commonly
used in Europe or Lightweight Concrete Blocks used for internal cavity
wall construction methods, both materials mentioned cannot withstand
heavy steel beams sitting on them, especially if a minimum bearing of
150mm is needed by Building Control and considering that the steel's not
to penetrate through to next doors property. Party Wall surveyors if appointed make
sure that the installation of steel beams is maintained only on the side of the building owner and not to be positioned past the boundary line of ownership. The steel spans designed by the engineer have to be redesigned spanning from front to back instead of side to side direction. Usually, the front and rear walls of the house are Cavities and are a lot thicker, either Blockwork or Brickwork only the dividing party wall is constructed cheaply in a few houses to save cost in construction.
Examples of Types of Non-Load-Bearing Party Walls
Dagenham - Semi - detached property
Wanstead - Mid Terraced Property
MIX OF BLOCKS AND BRICKS
Enfield - Semi - detached property
CONCRETE SLIP PANELS
Barnet - End of Terraced Property
THE ENGINEERING DESIGN SOLUTION TO AVOID LOADING ON ANY WEAK PARTY WALL
The objective is not to load the Party Wall when designing Loft Conversions, the weight of steelwork including the floor will slice through Terracotta Blocks like butter, so Spanning steels in the opposite direction would be the only viable solution for the new structure to work. Below is an annotation example of an Engineering Design to avoid side-to-side interference with the Party Wall's weak structure.
ATTIC FLOOR PLAN - N.T.S.
FIRST FLOOR PLAN - N.T.S.
All loading is spanning front to back on the main solid walls. Any additional mid-support, if needed, would be in a form of an intermediary supporting column, this in some cases cannot be avoided due to the large spans. Columns would reach ground level with newly designed foundations to withstand the loadings. This is a very expensive option as would destroy an already fitted Kitchen or a bedroom wardrobe if already installed. The number of steels needed would bring the cost of a Typical Loft Conversion up to a further £3000+vat on materials for this solution. Some houses are not meant to be touched and without knowing what you are buying then you could be opening up a huge money pit to convert the property to your fashion and overall not getting the sale return back that you thought.
Summary - When Buying any new house that you are planning to develop, visit the attic, go inside the loft space, and inspect the walls if they are constructed out of brickwork then you're ok.
Any other material other than Brickwork on the Party Wall makeup would be to consult a qualified Engineer to establish the principle design before purchasing the house or even obtaining Planning Consent from the offset.
Please note that you will require structural calculations if any steel beams are designed within your scope of works, this will be charged separately to the engineer.
EACH PROJECT WE TAKE ON IS STARTED FROM SCRATCH SO EVERY NEW JOB IS DESIGNED WITH CARE AND EXPERTISE TO GET 100% SATISFACTION
I hope you understood this article and find it useful for your proposals we just want you to get the right results and not to make a mistake in doing the build the wrong way around as this could lead to further unnecessary delays. Regards John.
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