With any bungalow renovation, there will be areas where original construction need to be replaced or new construction must merge with existing.
Some of the materials and fittings used in the construction of bungalows 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 sourcing second-hand materials or finding replicas.
The dimensions of new framing timber differ to old framing. Original timbers are usually rough sawn and will vary in size, including sometimes being slightly larger than the nominal size. For example, a 4 x 2” (100 x 50 mm) timber could actually be 4¼ x 2⅛” (107.9 x 55.25 mm). New nominal 100 x 50 mm framing is actually 90 x 45 mm.
The differences in timber size can be dealt with by:
- packing new framing to increase thickness
- adjusting packing to give an even line
- aligning a change with an internal wall location so the change in wall thickness is masked
- removing the existing wall back to a junction for small areas, then installing new framing
- having new oversized framing run – this will incur a set-up cost at the supplier
- use roughsawn H1.2 timber.
Where existing timbers are damaged, a decision must be made whether to retain or replace boards and to what extent. Damaged boards such as split, bowed and cupped weatherboard compromise the weathertightness of the building and will need to be replaced.
The decision whether or not to replace boards must take account of the availability of matching materials to make the repair and the risk of further damage to boards during removal (Figure 1). Minor splits may be able to be filled with flexible exterior filler.
The original timber species used for the weatherboards and finishing timbers may not be available or only available in limited amounts, although this is not a problem for painted weatherboards as the timber is concealed by the paint coating.
Modern standard timber cladding profiles are metric, not imperial, so an exact match, particularly for rusticated weatherboards, is not possible. Other options for matching weatherboards include:
- having matching weatherboards made as a special run
- obtaining an exact match replacement from a demolition yard
- increasing the lap so that bottom edges line up for bevel-back boards
- making the change from old to new timber at an external corner (where other corners in the weatherboard are not mitred)
- masking the change with a coverboard to make the difference in size less obvious.
The metric corrugate roofing profile is different to the imperial size roofing that may still be in sound condition. Where one or two sheets need to be replaced, new material can be used, but for larger areas of replacement, the profile difference cannot be accommodated. If second-hand material is available, it may be able to be used. If not, the roof will generally need to be replaced. The use of new long-run roofing eliminates the need for end laps, which have a greater risk of deterioration.
Marseille roof tiles are still available but may be manufactured to a different size. If this is the case, it may be possible to source a small number of matching tiles, but where a significant number of tiles need replacing, new tiles are likely to be required. (As good as they are, original Marseille tiles on a bungalow are likely to need replacing.)
Standard interior timber moulding profiles such as skirtings and architraves that are now available are in metric dimensions, not imperial, which makes an exact profile match where they abut impossible.
Other options for matching interior finishes include:
- removing all existing trim in the room and replacing it (use the removed material to make good or repair in other rooms)
- having new profiles run to match the existing
- sourcing second-hand material.
In some cases, damage may able to be repaired in situ by the judicious use of specialist fillers, or by filling and painting, which means the natural timber appearance is lost but the profile is retained.