Rarely do multicoated roofs need to be stripped down to bare timber. It is much more common for them to be stripped of wet and decayed material until a firm base is found. This base may need to be consolidated by various means before the new coat of thatch is fixed.

Coating of existing thatched roofs is achieved by the sway (hazel, straw bond or, occasionally, twine or steel rod) being fixed with twisted spars. Spars are split coppice wood, usually hazel but sometimes willow, pointed at each end and twisted in the centre to form a hairpin-like peg. The spars are driven through the new thatch into the base. Hence the need for a good firm base.