Buying a property is a daunting experience. Throw in the mix words such as “damp”, “cracking” or the dreaded “Japanese Knotweed” and it can make the whole experience a mine field!

As RICS regulated surveyors we aim to make our reports as reader friendly as possible and easily digestible as possible. Below a are range of terms used together with a basic definition. We aim to add to this page over time to make a comprehensive resource for everyone.


The apex (top) of the roof.


The diagonal join between abutting roof slopes.


A tall triangular outer wall.


The expose wall to the side of a structure.


The diagonal gutter between abutting roof slopes.

Fascia Board

The board which the gutters are attached too.

Soffit Board

The board which closes the void between the fascia board, and the structure.


The long horizontal support beams to support the roof structure.


The diagonal timber support to the purlin within the roof structure.

Cavity Wall

An inner and outer skin of brick/blockwork, separated by an air void (cavity). These walls can also have insulation placed in the void.


The support beam over a window or door opening.

Damp Proof Course

Since 1875 there is a legal requirement for properties to have a physical water barrier to stop ground water entering the structure.

This is usually a thick black impermeable membrane between two courses of bricks, just above ground level, running around the whole building. This single item keeps rising damp from occurring.

Combination Boiler

This provides space heating (central heating to, commonly, radiators) as well as instant hot water to the tap outlets, therefore the system is “combined”.

'Combi' boliers remove the need to have an insulated hot water cylinder.

Open Vented Boiler

This system heats water which is pumped around the property via pipework and radiator system to provide space heating only.

Open vented hot water

A cylinder which stores water within and is heated, ready to come through the water outlets when taps are opened.

The hot water is either heated through an electric immersion heater or via a hot-water spur, with a three-way valve, from the central heating boiler.

Three-way valve

A three-way valve is used to allow a, normally, gas boiler to heat both the hot water and the central heating. The three positions are:

  1. Hot water only (useful in the summer)
  2. Central Heating only
  3. Heating and hot water