First Steps in the Recovery of Alberta’s Flood-Damaged Historic Buildings
As the floodwaters in southern Alberta recede, we must take care to preserve the integrity of our historic resources. It is very important that old and historic buildings dry slowly. Accelerated drying will warp, twist or split floors, doors and paneling; draw salts through stone and plaster, leading to blistering and exfoliation; and painted surfaces will flake and peel.
Historic buildings are particularly vulnerable to damage from inappropriate remedial work after the floodwaters recede. This can lead to unnecessary removal and loss of significant finishes and fittings as well as use of unsuitable materials for repairs. Building conservation is concerned with retaining original historic fabric and cleaning or repairing it sensitively with the least impact, even in the aftermath of a flood.
The slow and gentle process required to save irreplaceable historic fabric may take several months and involves a number of steps.
Consult with Emergency Services
Ensure that the building’s electrical, gas, water and waste lines are safe and operating normally and that the building is structurally sound.
Document the Damage
Take photographs or videos and make notes about the damage to your historic building to assist with future planning for repairs and restoration.
Reinstate Drainage Systems
Clear debris and open blocked underground and surface drainage systems to help remove water from the building and its foundations. Use sump pumps or temporary pumps to help remove water from basements, although if water continues to rise pumping should be postponed. In that case, the water table is still high and the difference in pressure between the waterlogged soil and the water-less basement could damage foundation walls.
Identify Moisture Reservoirs
Debris, insulation, and piles of earth can prevent moisture from draining or evaporating. Identify current or potential moisture reservoirs to help specialists determine positions for localized drainage and through-the-wall ventilation that will allow long term drying and prevent decay of vulnerable materials.
Remove Only Non-Historic Furnishings, Fittings, Carpets, and Rubbish
Consult with your Heritage Conservation Adviser about damp historic materials such as plaster, brick, masonry, floors or finishes. Most historic materials are inherently durable and resistant to flooding and can often be carefully dried and restored.
Clean Mud, Dirt and Debris from Surfaces
Mud and debris deposited during the flooding can be removed with clean water and is more easily removed while still wet. Do not use high-pressure water to clean historic materials: pressure-washing historic material can do more damage than the flood itself.
Drying Out Slowly
Remove moisture gradually. Use natural ventilation to slowly dry the structure and historic finishes, particularly plaster and wood. Do not use mechanical dehumidification or heaters to accelerated drying. Fans may be used to circulate cool air. Open windows and doors to assist with ventilation. Install security protection and screens on windows and doors that will be open for an extended period of time.
Carefully remove water soaked gypsum board, which can trap mold spores. Do not remove plaster or wood finishes and consult with your Heritage Conservation Advisor about strategies to dry and stabilize historic finishes.
Plan for Repairs and Restoration
As the drying process takes place, observe any long term damage to historic fabric and initiate discussions with your Heritage Conservation Advisor and qualified specialists to plan repairs to your historic building and restoration of its historic materials.
For more information contact your Heritage Conservation Advisor:
Calgary Region: Sandy Aumonier (403-355-4544) and Stefan Cieslik (403-297-4074).
Southern Region: Fraser Shaw, office: (403) 297-4088 and cell: (403) 921-8139.
These numbers are toll-free by first dialing 310-0000.
Written by: Eileen Fletcher, Heritage Conservation Adviser.