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Choosing a Surveyor

Party Wall Compliant Drawings


What do we mean by ‘Party Wall Compliant Drawings’?

The core requirements to producing Party Wall compliant drawings is that they are sufficiently detailed that:

a) They satisfy all the legal requirements of the Party Wall Act.

b) They are sufficiently detailed that a Party Wall Surveyor, on review, can clearly ascertain the full extent of the proposed works.

c) They reflect the provisions that will later be included in the Party Wall Award. As experienced Party Wall Surveyors we are able to anticipate to a high degree of accuracy the terms and details that will likely be included in the future Awards and where applicable will show these on the drawings. Should your Party Wall Surveyor later request any further amendment or addition to the drawings, these will likely be small and we will provide these promptly and without any further cost.

As the above indicates, ensuring that drawings are Party Wall compliant requires that consideration be given to the specific works and how they could affect neighbouring structures. There is no ‘one size fits all’ in this approach and it takes a certain level of expertise in Party Wall matters in order to anticipate the relevant drawing details to include.

Party Wall Compliant Drawings in terms of Foundations and Structure: Party Wall compliant drawings generally have to be detailed and comprehensive both in regards to the foundations and in relation to the structure. The following aspects need to be considered:

Foundations: The Act requires that foundations within the specified distances (3 m or up to 6 m from neighbouring structures) be shown as cross sections on the drawings together with their location depths, foundation types etc. The Act will often require that these foundations be ‘eccentrically loaded’. Differential movement between new and existing foundations has to be considered and, in some situations, sequenced hit-and-miss foundations may be required. Soil conditions and propping of open trenches may need to be considered. In the case of basement design, a detailed design of the retaining walls etc. would need to be included. The Party Wall Act allows foundations to straddle the boundary line in certain scenarios and where this is the case, the boundary line will be shown as situated at the mid-width of the foundations.

A Foundation Cross-section drawing showing both depths and design are required in order to serve Party Wall Notices

foundation jpg

Design of Structure: This is a very broad category and includes all aspects of the works that affects the Party Wall. Any chimney breast removal on the Party Wall needs to be shown together with the method of supporting the breast and chimney stack above. Where new structures are proposed to connect to the Party Wall to the front or rear of the property, then a method of preventing differential movement between old and new walls will be shown. Any cutting-in to fix flashing in order to close gaps between neighbouring walls would be shown. Drawings need to show the works on Plan, as Elevations and as Sections. Where specific Details drawings are required to show how the Party Wall will be impacted these will be included. Method Statements may be provided on the drawings, as applicable.

The drawing below shows a flashing detail between a new ground floor rear extensions (to the right of the drawing) and the neighbour's existing extension (to the left of the drawing). The purpose of including the flashing detail was to show how water and airborne debris should be prevented from becoming stuck between the two extensions in order to avoid internal damp problems from occurring.

Another point of interest about this drawing is the fact that the boundary line (shown in dotted red) runs through the thickness of the flank wall of the proposed extension. In this case, the owner had a right to erect the wall straddling the boundary line, so circa half the thickness of the wall is on his land and half is on his neighbour's land.

Flashing Detail
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