Remedies: Matching new to existing

With any villa renovation, it is likely that there will be areas new construction is being merged into old, or where small areas of original construction need to be replaced.

A number of the materials and fittings used in the construction of villas are no longer readily available. While timber profiles can be run to match existing, the options for sourcing other materials and fittings are generally limited to second-hand materials via demolition sources or replicas. 

Framing sizes

New framing timber has different dimensions from existing villa framing. Original timbers are usually rough sawn, will vary in size between individual lengths, and are likely to be slightly larger than their nominal size. For example, a 4 x 2” could actually be 4¼ x 2 ⅛” (107.9 mm x 55.25 mm). New nominal 100 x 50 mm framing is actually 90 x 45 mm.

Options to deal with the differences are: 

  • pack new framing to increase thickness, adjusting packing to give an even line 
  • make the change coincide with an internal wall position so that the change in wall thickness can be masked
  • for small areas, remove the existing wall back to a junction then install new framing
  • have new oversized framing run – this will incur a set-up cost at the supplier.



Roofs to new extensions can be readily merged into the existing using trussed roof construction, as it is relatively simple to match the eaves detail of the truss to the existing ceiling joist top plate detail.

Corrugated iron

Current metric corrugate roofing profile is different from old imperial material that may still be in sound condition. Where one or two sheets are being replaced, new material can be used, but for larger replacements, the profile difference cannot be accommodated. 

Second-hand material may be available. If not, the roof will generally need to be replaced – using new long-run roofing also eliminates the need for end laps, which have a greater risk of deterioration.

Clay roof tiles

Clay roof tiles are unlikely to be available new. It may be possible to source a small number of matching tiles, but where a significant number of tiles need to be replaced, or for additions to the villa, it is likely that new roof tiles will need to be specified.

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Where existing timbers are damaged, it is a judgement call as to the need to replace. Some wear and tear over a long period of time can add to the character and therefore may be acceptable. Where there is damage such as splitting, bowing and cupping in exterior timbers that are a key part of weathertightness, they will need to be replaced.

Any decision to replace timber needs to take account of the availability of matching materials to make the repair and the risk of further damage occurring during removal. 

Original timber species used for weatherboard and finishing timbers may not be available, or only available in limited amounts. For painted weatherboards, the species is less relevant as the timber is usually hidden by a paint coating.

Current standard timber cladding profiles are metric – not imperial – and an exact match, particularly for rusticated weatherboards, is not possible. Design options can include:

  • having matching weatherboards run as a special
  • obtaining an exact match replacement material from a demolition yard
  • for bevel-backed boards, increasing the lap so that bottom edges line up
  • making the junction at an external corner or mask with a coverboard, which will make the difference in size less obvious.

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Current standard interior timber moulding profiles like skirtings and architraves are now metric – not imperial – making an exact profile match where they may need to abut impossible. Options for design can include: 

  • removing all existing trim within the room and replacing it – use the removed material in other spaces to make good or repair
  • having new material run to match existing profile
  • sourcing second-hand material.

In some cases, damage may able to be repaired in-situ by the judicious use of specialist fillers or by considering filling and painting, which will lose the natural timber appearance but retain the profile.

A number of villas were constructed using interior trims machined from thicker timber to give a more substantial trim – typically 30–40 mm thick. These timbers can also be reproduced but they can be expensive due to the set-up costs and the amount of (scarce) timber that is cut to waste during machining.

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Glass becomes brittle with age and difficult to recut to new sizes. It’s also difficult to perfectly match original colours with new glass. Repair options can include:

  • replacing of all of the colour that might have a single piece broken
  • remaking the window with new coloured glass
  • finding an exact colour and size match at a demolition yard.