Introduction to Timber Frame Construction

 Timber frame construction is a modern method of construction (MMC) employing standardized and prefabricated timber wall and floor elements. It is commonly used in developed countries.

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Timber frame construction employs breathable membranes, insulation, and vapor control layers, without compromising their durability. 

All the building regulation requirements like fire, acoustic, and thermal requirements are also incorporated into the timber frame design.

Working of Timber Frame Construction

A timber frame building includes:

1. Engineered Walls
2. Engineered Floors
3. Engineered Roofs

A timber frame design uses timber studs within the external structural walls to carry the loads imposed before transmitting them to the substructure. 

Major Elements of a Timber Frame Construction

The main elements of a timber frame construction are:

    1. External Walls
    2. Non-load Bearing Walls
    3. Separating walls
    4. Intermediate Floors
    5. Roof
    6. Foundations

1. External Walls in Timber Frame

The figure-2 shows a typical external timber frame wall section. The timber frame is the load-bearing element of the structure. It supports both dead and imposed loads from the floors and roofs, along with resistance to wind loads. 

The external walls of the timber frame are composed of:

• Plasterboard lining
• Polyethylene vapor control layer (500 gauge)
• Structural timber frame ( 89 x 38 mm or 140 x 38 mm studding)
• Insulating quilt or bats fixed between the studs
• Sheathing boards
• Breather membrane
• Wall ties
• External skin - brickwork, render, tiles or weatherboarding

Fig.2. Timber Frame External Wall Cross-Section

The studs for timber frame panels are usually spaced at 600 mm. Integral timber lintels are used to support openings in load-bearing panels. Additional studs are used to take point loads imposed by beams, girders, or any concentrated loads. To carry higher loads, the stud spacing can be reduced. 

2. Non-Load Bearing Walls in Timber Frame

These walls are made of stud frames with a depth of usually 89 mm. Plasterboard batts are fixed between the studs to provide sound resistance. 

The timber frame package provides all the internal partitions, and framing for cupboards, reducing the amount of site-required carpentry to a minimum.

3. Separating Walls

Separating walls are formed by having a clear cavity between independent panels, with multiple layers of insulation batts and plasterboards.

4. Intermediate Floors

Floor panels (or cassettes) are often used to form intermediate floors and can consist of solid timber joists, ply web or metal web beams, or other types of the beam.

5. Roof for Timber Frame

Roofs are formed with trussed rafters, although roof panels are a possible alternative. In the case of timber frame, the head binder of the wall panels provides a ready-fixed, level, and straight wall plate on which to fix the trussed rafters. 

6. Foundations of Timber Frame

The depth of foundations is governed by building regulations requirements to avoid the effect of ground settlement or heave, while the minimum width of footings is determined by the width of cavity wall construction.

Timber frame construction is a lightweight construction that offers potential savings on the foundation. Timber frame construction consumes less time and is less affected by poor weather. These designs demand experienced erectors, the accurate placing of elements, and good quality timber.