Home Damage Resources Windows Doors Ceilings Roofs Walls Services Furnishings Re-building Damaged Homes - Wall Repair and Replacement : By Richard Edkins Introduction : This is perhaps the most dramatic kind of repair. In most cases, it will be sufficient to strip down damaged sections of wall and rebuild them, but the destruction of towns and villages by deliberate malice may mean rebuilding streets of houses. If foundations remain intact, one can construct a strong building on their support, maybe even taking advantage of surviving water and sewerage piping and electrical power mains. If a ground floor survives from a two or three-storey house, it can be roofed and used as a bungalow. The work involved is quite laborious, so is best done with others in the community, house by house, as in the grand old American tradition of the 'House Raising Bee'. The kind of wall repairs needed with Class 4 damage will be fairly minor, mostly involving plasterwork, unless the building has an underlying structural weakness. In the case of Class 3 damage, internal partition walls may be broken or destroyed and some load bearing walls may be affected. At Class 2 damage, outer/load bearing walls (in the direction of any blast, or in a severe fire) will be cracked and may collapse, whilst at Class 1 damage, the building is little more than a pile of rubble about upstanding chimneys, staircase structures and adjacent wall elements. This section therefore concentrates on repairs to Class 2 and 3 damage, but does consider the possibilities of reconstructing even a Class 1 level of damage. One of the advantages of a complete collapse is that unstable walls remove themselves and reconstruction may actually be easier. The cause of damage is critical when considering building repairs to walls. An earthquake vibrates a structure from the bottom up, so the top tends to 'whip' around and fracture, whilst lower sections may be undamaged. Explosive blast crushes and collapses directionally from the point of detonation, the blast wave and the following 'blow-back' felling walls before the blast wave but sometimes leaving walls in line with the blast direction undamaged. The curious appearance of buildings with walls 'bent double' like a boxer hit in the stomach, may occur before collapse. Fires, by contrast, remove the floors and other burnables, causing thermal shock and wall-cracking to brick, stone and concrete. Thermal expansion of steel within reinforced concrete can cause spalling; exposure to fire will then bend or even melt the steel, causing structural collapse. The repair of concrete and steel structures lies outside the scope of this section so will not be considered. Careful demolition of upper sections of damaged structures to safeguard lower floors, then their re-roofing to keep out rain and wind, was used successfully after earthquakes near Naples in Italy. As for the resistance of modern structures to blast and shock, the 1988 air disaster amazed the writer by the state of a bungalow in Lockerbie barely thirty yards from the impact crater in Sherwood Crescent. The roof had moved a few centimetres but remained intact except for a few tiles damaged by debris. The walls of the structure were intact, whilst a triple-glazed door and secondary-glazed windows were still in good order. Debris had badly starred the outer pane of the triple-glazed door, the middle pane was cracked but the inner pane was undamaged. A few power cables had parted, but could be re-connected. A single-glazed house would have lost its windows and been uninhabitable. Alternative Walling Solutions : Coming to the materials for rebuilding a wall, the best ones to use should match the originals. Failing that, the following expedients are suggested in order of preference for repairs. New structures are best built of one particular material to ensure uniformity of expansion :- Replacements for cement mortar :- (a) : Lime mortar, possibly mixed with finely-crushed broken tile or ash as a pozzolanic cement. (b) : Lime mortar on its own. (c) : Lime/clay mixtures. (d) : Clay/grit mixtures. (e) : Clay and chopped straw. (f) : Clay and animal dung (remarkably effective). Wall materials :- (a) : Salvaged brick or blockwork laid dry or mortared. (b) : Stone or broken concrete laid dry or mortared. (c) : Rammed earth (cob) - block or rammed in moulding. (d) : Wattle and clay or clay/dung daub in timber frames. Damp proof courses :- (a) : Bitumenised felt or heavy flexible plastic. (b) : Two layers of slate, tile, or glazed brick, laid to break joint. (c) : Re-melted road tar or asphalt. (d) : Melted rubber from old tyres. (e) : Pitch melted from spruce and pine tree stumps. Ground Floor materials :- (a) : Planking or panelling on dwarf walls or joists. (b) : Flat tile on mortar screed on dry hardcore. (c) : Mortar and pounded tile screed on dry hardcore. (d) : Rammed clay floor on dry hardcore. (e) : Rammed clay floor on ash. Alternative Interfloor structures :- Interfloor elements consist at the least of joists and planking, preferably with some kind of ceiling for reasons of comfort. There are very few effective substitutes - strength is vitally important - but the following might be considered :- Joists :- (a) : Smaller section timber or planking fastened or strapped together to replace damaged joists. (b) : Box-sections of planking spaced closely together and cross-braced. (c) : Three or four layers of long branches or small poles, each layer at right angles to the other and wired or lashed together at crossing-points. The multiple layers give strength in the same way as a honeycomb or a Bailey Bridge. (d) : Scaffolding tube or small poles reinforcing dry brushwood faggots lashed or pegged together - resilient, insulating. Most suitable for upper room ceiling below loft level, as not designed to carry heavy furniture loads. Flooring :- (a) : Any reasonably strong planking or panelling, pegged or nailed to joists. (b) : Laths, cane or split branch or stem timber. May need to be in layers. A building with a surviving masonry or brickwork ground floor could be restored to first floor level by building a wooden framed wattle and daub upper storey. This tactic could restore living space and is a surprisingly good permanent solution if properly maintained. Surviving examples from the 1600s are standing in towns throughout Europe. Cob walls still survive in many nations; adobe and sun-dried brick are just two versions of it, all improved by a rendering of lime plaster or tar or limewash and wide-eaved roofs. Laid on stone or concrete foundations, with a damp-proof course and broken glass in the lower wall against rats, such houses are excellent. Drystone walling can form the outer wall of a house and can last for many years. Bedding the stone in strong clay or lime mortar turns the stone into a compact mass with a life of centuries. Home Damage Resources Windows Doors Ceilings Roofs Walls Services Furnishings © 2003 Richard Edkins. Site maintained by Dalbeattie Internet. Last Updated 16th April 2003.