The Construction Centre
Magnifying Glass

Repairing Flood Damaged Property

For up to date information call Floodline on 0845 988 1188

Repairing Flood Damaged Property

The links below jump to the relevant section on this page:

One of the first steps to take is to assess the damage to your property. You can either perform this check yourself initially or if you know there are problems, engage a professional surveyor to look at the structural integrity for you.

A structural assessment of the building can be made by:

  • Checking roofs: roofs are a very good indicator of the presence of structural damage. Look at the ridge of the roof and assess whether it has changed - this should be viewed from a distance rather than close up
  • Checking the walls: this is to verify that they are as before and can normally be done by eye or with a spirit level
  • Displacement:Look for bulging or dislodged sections of the building fabric/structure
  • Scouring: Look for deep scouring which has led to the foundations being exposed
  • Cracks: Check for any new cracks bigger than 5mm (or 1/4 ") above doors or windows

If any of the above features are observed, a building professional must be called in to assess the property. It is important to make regular checks for damage, at least once a day, as it may take a while for some damage to become apparent.

The British Damage Management Association (BDMA), the certifying authority for practitioners in flood recovery and restoration, warns that incompetent restoration work can lead to health risks and irreparable damage to building structures. They recommend using a reputable recovery agent that is experienced in dealing with flood damage. The BDMA advises that credentials should be checked and take the insurers recommendations first.


A brick dries out at the rate of about an inch a month, so it may take several months for the brickwork to be completely dry.

Dry the brickwork as effectively as possible – natural evaporation is the best method if the weather is dry. Brickwork, particularly old bricks, may deteriorate and require repair work.

Wet brickwork is susceptible to frost damage and can spall and flake or even crack. Bricks may shrink or crack as they dry. Record any cracking and, once the crack movement has stabilised and the cracks are fully open, fill them. However do not re-point or repair cracked brickwork or masonry until the foundation soil has dried out and foundation movements have stopped.

During the drying out stage you may see a white salt growth on bricks and concrete. This will stop when the wall is fully dried and should be removed with a bristle broom. If the brickwork is painted then allow it to fully dry before attempting to re-paint, wet brickwork will stain through emulsion and lift off oil based paint.

If the brickwork fails to dry then obtain samples of the masonry and have them tested them for moisture content and hygroscopic salts. This will indicate whether there is a rising damp problem, in which case, seek specialist expertise.

It is important that any air bricks are removed once the flood has receded, as they are essential in allowing ventilation of the wall cavity. Removing air bricks will aid in drying the building out and allow any trapped water to dissipate.

Wall Coverings

Remove loose wallpaper or other wall coverings. Be aware that you may also need to remove tiles.

Low permeability wall coatings, like vinyl wallpaper, gloss paint and tiling, will slow down drying of masonry partitions and could cause rotting in timber stud partitions. Remove such coverings from at least one side of internal walls to speed up the drying process.

Redecorating should be left for at least three months after repairs have finished. Painting or papering too soon may result in mould, blistering and peeling. When repainting emulsion, staining may occur but this can be avoided by using an oil-based or stain-block paint before final painting.

Floorings and Floors

See the section on drying Floors in Drying Out

Glass and Windows

Flooding can lead to the breakdown of the edge seal in double glazing. Check for mud and water stored in hollow window and door frames and drain any contamination found by drilling a drain hole at top and bottom of the frame. If you can see condensation between the panes, replace the double glazed unit. Single glazing is largely unaffected unless completely broken; however, check the condition of putty and window locks to ensure the windows are secure.

Sash windows may distort following a flood. Care should be taken not to force sash windows and cause further damage. As they dry out, swelling of the wood will reduce and they may return to full function. If the window needs to be open to aid drying remove beading and take out the opening sash, do not plane the sash down until the wood is totally dry and the fit has been tested.

Temporary beading can be screwed into position to provide security when the building is unoccupied.

Clean all windows, window locks and hinges and oil them to prevent corrosion.


Remove any insulation that has become wet as it will retain water and slow the drying out process. It may need to be replaced as it tends to reduce in thickness and effectiveness.

Cavity wall insulation may have become damaged by flooding. If you think that this is the case, seek expert advice - you may have to have the insulation replaced by specialist contractors.

Wear protective equipment (e.g. clothing, gloves, goggles and a face mask) when removing fibreglass insulation as it is an irritant.

Plaster and Dry Linings

Unless the flood was only a few minutes in duration, materials and components containing Gypsum will absorb large quantities of water and begin to distort. Plasterboard dry-linings or insulated plasterboard fixed to the wall with plaster adhesive will need removing and replacing up to at least the height of the water mark if they have de-bonded (partially separated out into layers).

Remove the skirting boards and cut or drill holes through the plasterboard or dry-lining to drain out trapped water and to aid drying out. If the plasterboard or dry-lining are beginning to distort remove up to at least the high water mark, let the timber studs dry out and then replace. Plasterboard would need to be renewed (consider replacement with wooden dry lining) but wooden dry-lining can be dried and re-used.

Any plaster that is dry on its surface can be redecorated if it is in good condition and has been cleaned thoroughly. Ensure the whole surface is dry (ordinarily light pink in colour).

Replace detached, friable or damaged plaster, but wait until it becomes apparent that crack movement and salt deposition (i.e. the formation of salt crystals on the surface) has ceased. Where you have to replace plaster, consider using an alternative that is less vulnerable to damage in the event of another flood, for example use tanking.

See also the section on Walls in Drying Out.


Decay of wood is unlikely if the wood dries out within a few weeks. However, if the wood remains damp for longer periods of time then the threat of decay becomes greater.

With wood framed walls, it is essential to expose any wood up to the tide mark (highest level of flood water). Also remove plasterboard, vapour control membranes and insulation unless the flooding was very limited (only lasting a few hours), less than 150mm or 6" and the moisture content of the wood is less than 20%. Any specialists will have a moisture meter that can be used to measure the moisture content of the wood and they should be contacted if you are in any doubt over damage to your property.

Wooden window frames may jam when wet (due to expansion after water absorption) and become distorted as they dry. The distortion may cause the frame’s paint to flake off. Therefore check the moisture content of the wood and also check for signs of rot. If necessary, repair and treat the wet timber with preservative plugs. Once dry, the frames can be redecorated.

Wooden staircases may become unstable and weakened so check the support of the staircase and, if necessary, strengthen it with extra struts under the floor. Stabilise loose treads once the staircase has dried out.

Fire doors are often constructed with layers of fire resistant compound hidden in their cores. Soaking in water can permanently damage these doors. Replace all fire doors that have been immersed in flood water.

Remove plinths from floor-mounted cupboards and kitchen units and dry out, clean and disinfect the void and the area behind the cupboards. Cupboards and kitchen units are frequently made of laminated chipboard which can be severely damaged by flooding. The chipboard may expand or distort and lose its strength. It can also be impossible to disinfect properly. If this is the case the units will need to be disposed of and should be replaced. If there is a risk that flooding may re-occur, consider replacing laminated chipboard units with those made from materials less vulnerable to damage, such as stainless steel or aluminium.

Electrical Systems

A properly qualified electrician must check the building’s electrical system, repairing all components that may be damaged by water immersion or short circuits. The electricity supply to the property must remain switched off until all the relevant checks have been done.

As part of these checks, junction boxes, socket outlets and in extreme cases light switches and ceiling roses should be examined for trapped water or moisture, especially those beneath suspended ground floors.

Modern wiring can withstand short periods of flooding but after long periods in water the insulation of cables may be compromised by water or silt. In this case the wiring will need to be replaced.

When replacing wiring and sockets, it may be sensible to re-route cables to drop down from above to socket outlets on the ground floor. If there is a risk of further flooding in the future it is advisable to raise socket outlets to at least 90cm (3’0") above floor level on the ground floor.

Electrical equipment must be allowed to dry thoroughly and should be checked by a qualified repair person before use.

A temporary alternative electricity supply may be possible with a generator. Be aware that these may be in short supply following a flood, so share with neighbours where possible and only use essential electrical equipment.

Gas Systems

Water and mud may get into the gas system and appliances during a flood, affecting their safe operation. It is vitally important for safety reasons to have appliances inspected by a Gas Safe Registered engineer.

The appliances may light and appear to be working normally but the flue or ventilation systems which are essential for normal working operation may have been adversely affected by the flood water or partially filled with water.

You can contact a Gas Safe Engineer via the official website.

If you live in Local Authority or Housing Association property, contact your landlord as soon as possible.

If you can smell gas in your home call TRANSCO immediately on 0800 111 999.

Water Systems

Generally water systems (where they are supplied directly from the water mains) should not be affected by flooding, but check pipe work to ensure that it has not been damaged to allow contaminated flood water to enter the system. You will also need to check and dry any insulation on the pipes and replace as necessary.

Your local water supplier will notify you if water is to be cut off or restricted. Run taps for a period (a good sized bowl full) before use to see if silt has made its way into the system. Occasionally the mains water supply may become contaminated. If in doubt contact your water authority and boil all tap water for at least 20 minutes before use.

Wells and cisterns may be contaminated and should not be used until tested over a period of time. The requirements for this are set out in the Private Drinking Water Supplies Regulation which should be consulted.


Public sewers

Drains and sewers often become blocked and back-up in flood situations. Drains and sewers are rarely damaged in floods, but can be checked by flushing toilets and running taps. Contact your local sewerage undertaker for advice and to report any blockages. Consider fitting an anti-backflow device if sewer repairs are undertaken.

Private sewage systems

Flooding of a private sewage system can be a hazardous situation for homeowners. It may lead to a back-up of sewage in the home, contaminated drinking water and lack of sanitation.

When flooding or saturated soils persist, a private sewage system may not function properly. You should not use the sewage system until water in the disposal field is lower than the water level around the house. Damaged septic tanks, cesspools, pits and small package sewage systems should be serviced as soon as possible. If you suspect damage, have your system professionally inspected and serviced.

Severn Trent Water has now adopted many sewer pipes across the UK which means that in the case of flooding or blockages, they are now responsible for resolving the situation. If the problem is in the pipework between the house and the main sewer, this is still the responsibility of the homeowner.

Signs of damage include settling or inability to accept water. Sometimes tanks or pump chambers become filled with silt and debris and must be professionally cleaned. The disposal field may also become filled with silt. Remember that damaged sewage systems are health hazards and any repair work should be carried out by trained specialists.

If flooding is likely to re-occur it is important to ensure that septic tanks are kept full. Should they be empty during a flood, there is potential for them to lift out of the ground and float away.

See also You have been flooded

Useful Links