Research into the problems caused by driving rain on exposed solid stone buildings DAMP TOWERS PROJECT English Heritage University of Oxford Sheffield Hallam University Colin Burns Ridout Associates Architects and Contractors

This talk water penetration potential remedies climatic futures the research project: site testing and monitoring laboratory simulations results

The Problem failed repairs construction history moisture movement testing & monitoring

St Michael’s, Princetown

Ypres Tower, Rye, E Sussex

St Senara, Zennor, Cornwall

Winter rainfall predictions

Winter daily windspeed predictions 2050s Source: UKCIP, 2002

Traditional Repairs stonework pointing rendering grouting plastering

Questions to answer how does driving rain enter solid masonry? how does water, moisture, vapour move within solid masonry? what difference does wind pressure, humidity, time, temperature make? are there differences in types of rain?

Questions to answer what are relative differences between remedial treatments? are there examples of similar towers performing differently which treatments work best? to what extent are human faults responsible for performance?

Holy Trinity, Challacombe, Devon

Castle Drogo

St John the Baptist, Stowford, Devon

Laboratory Testing Sheffield Hallam University

Wall 1 Smooth Render Wall 2 Weathered joints Wall 3 Coarse finished render Wall 4 Repointed with OPC Wall 5 Control

Results of Phase 1 walls built with cement wetted up quickest & dried out slowest walls built with hydraulic and non-hydraulic lime mixes gave similar results walls built with hydraulic lime renders took longest to wet up and dried out quickest

Run 1 Run 2 Run 3 Run 4 Run 5 Run 6 Start date 03/08/ /09/ /05/ /10/ /01/ /05/2006 Testing Walls 1 & 2 as built Rendered walls 1 & 2, walls 3 & 4 as built Walls 1,2,3 & 4 all rendered Walls 1 & 2 plastered, walls 3 & 4 rendered Walls 1 & 2 plastered, walls 3 & 4 grouted & un-rendered

Tentative Results from Phase 2 whole of the wall acts as a system saturated walls without voids do not discharge water on the inside face walls with voids do discharge water on the inside face size of voids does not seem to make any difference

Tentative conclusions render is very effective at reducing water intake in voided walls lime putty render takes on more water but dries faster than hydraulic lime render grouting very effective especially for large voided wall during prolonged rain grouting only effective when voids filled plaster effectively reduces rain penetration

University of Oxford

Wytham, nr Oxford

Application to lighthouses understand the problem treatments depends on building & problem building needs to be considered as a complete system use traditional materials controlling indoor environments maintenance and monitoring