A mansard extension can create a substantial amount of additional living space.
It can also involve much more Party Wall work than a straightforward roof refurbishment.
If you live in a terraced or semi-detached property, it is sensible to consider the Party Wall position early in the design process.
Why do mansard extensions frequently involve party walls?
Mansard extensions typically alter the shape and structure of the roof substantially.
Depending on the design, the works may involve:
- raising existing party walls;
- cutting new steel beams into party walls;
- altering parapets;
- constructing new flank walls;
- creating new roof abutments; and
- working immediately alongside the adjoining property.
Several of these can fall within the Party Wall etc. Act 1996.
Raising the party wall
One of the most common issues is increasing the height of the party wall to accommodate the new roof profile.
This type of work will normally need careful Party Wall consideration.
Structural steels
The new roof structure may require substantial steel beams.
Where these are supported within a party wall, notice may be required.
Your structural engineer’s drawings will therefore be important.
Weather protection matters
Roof works expose buildings to the weather.
A Party Wall Award may include practical provisions concerning:
- temporary weatherproofing;
- sequencing;
- protection of neighbouring roofs;
- flashings;
- making good; and
- access where legitimately required.
Speak to your neighbour early
Mansard works can look substantial from next door.
Early communication, supported by clear drawings, can reduce uncertainty.
Plan the Party Wall programme
Do not assume that planning permission is the last approval needed.
Party Wall matters are separate and should be programmed before construction starts.
Simple Survey mansard advice
Simple Survey regularly assists with roof and loft projects throughout England and Wales.
If you are planning a mansard extension, send us your architectural and structural drawings and we can advise on the Party Wall requirements.