When buying property, it is essential to understand its construction type. This knowledge can impact everything from Insulation and energy efficiency to future renovations and repairs. In many cases you may not need to rely on an expert to identify whether a building is constructed from solid brick, cavity Brick or timber frame; you can often tell by doing a simple visual inspection.
This blog will walk you through the visual clues that help distinguish between these common types of construction.
1. Solid Brick Construction
Solid brick walls are made entirely of brick, without any internal cavities. This type of construction was common in older properties, particularly before the first quarter of the 20th Century. Solid brick is valued for its strength and durability, but it is less energy efficient compared to more modern techniques.
Visual Clues for Solid Brick Construction:
- a) Pattern of the Bricks (Bonding Pattern) One of the easiest ways to tell if a wall is solid is by looking at the brick bonding pattern. If you see bricks laid in alternating rows of “stretchers” (long side visible) and “headers” (short side visible), you are likely looking at a solid brick wall. This is called English Bond or Flemish Bond.
- b) Wall Thickness: Solid brick walls are noticeably thinner than cavity or timber walls. If you can inspect a window or door reveal (inside edge) you may notice the width is around 220 mm although can be a little more when plastered or dry lined.
- c) The Age of the Property: Older Homes especially those built before the 1920s are more likely to be solid brick, as this was the primary construction method before cavity walls were introduced.
2. Cavity Brick Construction.
Cavity Brick walls consist of two layers (also called leaves) of bricks with a gap, or cavity between them. The cavity was initially introduced to prevent water penetration and later became useful for insulation purposes. This method became more popular in the late 1920s and is still used today.
Visual Clues for Cavity Brick Construction:
- a) Brick Pattern (Stretchers Only): The external layer of a cavity wall is usually built with bricks laid only with the longer side (stretchers) showing. This is in contrast to the alternating stretcher-header pattern found in solid brick walls. The absence of headers is a strong clue that the wall has a cavity.
- b) Weep Holes: Look for small, regularly spaced holes near the base of the wall, usually around 1-2 bricks up from the ground. These weep holes are designed to allow moisture trapped in the cavity to escape. Weep holes are unique to cavity construction and will not be found in solid brick walls.
- c) Wall Thickness: If you can inspect a section of the wall where it is exposed such as a window reveal, it will generally measure around 250mm thick, including the cavity. It may be a little thicker if dry lined.
3. Timber Framed Construction
Timber-framed homes are built with a structural wooden frame, and the brickwork, if present, is usually a skin applied to the exterior for aesthetics and protection and is often rendered. Timber framed houses are lighter and quicker to build compared to solid or cavity brick houses and this method is especially common in modern construction.
Visual Clues for Timber-Framed Construction:
- a) Outside on the external brick skin, look for ‘perpends’ (small vertical gaps between bricks, usually with a ventilated plastic spacer, above ground level at about 1.5m spacings). These are to ensure the cavity between the cladding and timber frame is ventilated and allows any moisture that does penetrate the cladding to drain away from the cavity and keep the timber frame dry.
- b) Look under the windows for horizontal gaps or compressed filler between the window and the brickwork. These are to allow movement between the timber frames that shrink as the timber seasons and the brickwork.
- c) Go into the loft. In semi-detached or terraced homes look at the party wall which separates yourhome from next door. If it is plasterboard-faced, your home is almost certainly timber frame. In any type of building, look for timber wall plates (the trussed rafters rest on these). In cavity construction these wall plates are left rough sawn but in timber framed houses they are planed smooth. It is sometimes possible to see the top of the wall at the eaves in a roof space, indicating that the inner skin is a timber structure. You can also check the gable wall. In a timber frame home, it will normally have a triangular panel with sheathing, forming the gable end.
- d) Knock on the inside face of an external wall. If it’s timber frame, you should hear the pattern of sounds made by the vertical timber studs. Meaning it the walls sound the same, uniformly wherever they are tapped because the internal dry lining plasterboard is screwed directly into the timber frame. You can also use a stud locating tool (available from DIY shops). Conversely in traditional, masonry homes the plasterboard is fixed directly to the masonry walls using a dot and dab technique which means that if the walls are tapped in the centre of the plasterboard, they sound very hollow but if tapped near the edges where they are fixed the sound is very different. Therefore, it would be important to tap the wall in a variety of different places.
- e) Timber-framed properties are a lightweight construction therefore they often feel less solid than brick-built ones. The exterior walls may sound hollow when tapped or you may see more flexibility in the structure during a close inspection.
- f) Turn off the mains electricity supply, then, in an external wall, unscrew the cover plate on a light switch or socket outlet. Sockets in timber frame homes are normally mounted on horizontal noggings. The socket box has holes through which you should be able to see timber and insulation.
Final Thoughts
Understanding the type of construction used in a property is an important part of sympathising its maintenance, renovation potential and energy efficiency and predicting any future potential defects. Whether you are considering an older home with solid brick construction, a mid- century cavity brick house of a more modern timber- framed home, paying attention to visual clues like brick patterns, wall thickness and weep holes can give you a clear idea of the structures build.
Interpreting the differences between these construction types not only helps you make informed decisions as a homeowner but can also prepare you for the long-tern upkeep and maintenance that each type requires. By using these tips, you can easily inspect any property and feel confident in identifying its construction type. If you are ever in doubt a qualified builder or of course a surveyor can provide a more detailed assessment.
