Spragging

When construction commences, and before the introduction of any concrete, the timber beams must be supported at intervals of one third of their length for the duration. As a rule of thumb: once the span exceeds 3 metres, it is advisable to sprag the timber ceiling before concreting. Once the concrete has reached 80% of its ultimate strength, the supports may be removed. The actual time for which the supports need to remain depends on the recipe used for making up the concrete mix and on the ambient temperature. The standard time is 28 days. If spragging from below is not possible, we can provide a patented solution for the suspension of the beams. Using transversally pre-tensioned heavy duty girders and a special tensioning system, the beam in question remains pulled up into a separate truss for  the period of construction, instead of being supported from below. Jointly with a Swedish restraining system manufacturer we have developed an innovative, economical solution that meets the requirements here; this has already been used successfully in a number of refurbishment projects.