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A Home Owner’s Winter Storm Damage Check-list

In Ireland, major snow storms happen every few decades. Snow build-up can affect buildings in complex and unexpected ways; what signs of damage should you check for?

Many homes built in the last thirty years may never have been subjected to a snow- load, or a prolonged period of freezing temperatures so we can expect some underlying defects to become apparent. Older buildings may also have deteriorated since their structure was last put to the test by heavy snowfall.

As the recent snows thaw, here are the three types of problems to look out for:

  1. Damage caused by the physical weight of the snow on roofs, walls and even foundations.
  2. Pressure caused by freezing water inside and outside, in pipes or on exposed surfaces
  3. Issues caused by melt- water and the force of driving wind, sleet and snow.

What Should I Look for After The Storm

Roofs

  1. Look for bent, sagging or deformed roofs (either slate, tile or flat roofs). It can be hard to notice subtle changes in roof shape, but they are important because they indicate torn membranes, loose slates and ongoing deterioration of roof timbers. A good way to assess this is to take a picture from outside and compare to pics of your house from before the storm. You can always obtain these on Google streetview.
  2. Missing slates or tiles are obvious. Call a roofer as soon as possible.
  3. Torn roof membrane (may be hard to see from the attic, because locations of holes are likely covered by roof timbers). This is the most likely damage at this time in my opinion, caused by the weight of snow bending the roof timbers. Check the attic for water droplets on the underside of the roof.
  4. Cracked flat roof membranes- especially fibreglass or fully bonded bituminous roof membranes. This may appear as staining on ceilings below over the coming months.

Gutters and Downpipes

  1. Look for detached, missing or deformed rainwater goods (gutters and downpipes.)
  2. Gutters and rainwater downpipes not flowing properly to remove melt-water from roofs. This is as dangerous to the house as any other blockage, it can cause water to overflow into the house. If possible clear any instructions as snow begins to melt.
  3. Detached, bent or deformed sheet metal work on roofs.

Inside the House

Inside, you are most likely to notice new cracks, stains or large leaks.

Staining and damp patches on ceilings and walls can be caused by:

  • Leaks in the heating system,
  • Roof leaks,
  • Overflow from the rainwater system, or
  • Condensation effects.

Ice Blocking Rainwater Systems (gutters, valleys, downpipes and gully traps.)

An unusual effect in very cold weather, is when melt-water is prevented from flowing off a roof properly by dams of ice or snow. This can cause water to flow over roof flashing, valleys or joints in waterproof membranes, which are designed to contain rainwater at a particular level. Snow raises melt-water above the top of these protective barriers. These may cause some water damage for a limited period of time, and the cause of the water ingress may not be evident after the ice blockage melts away.

Heating System Failures and Plumbing Leaks

Boiler Not Working

Boilers have safety features which make them cut off for a variety of safety reasons such as when the flue, air intake, or condensate pipes are blocked, or if there is insufficient water pressure in the radiator system.

The external openings could get blocked with snow or ice, triggering a cut-off. Don’t attempt any tasks which require you to dismantle or open up the system. I would suggest you gently remove any obvious obstructions from around the external openings for the boiler, and try the boiler’s “reset button” then try to turn on the heating again.

If this doesn’t work, contact your plumber.

You can often call your plumber for boiler issues and trouble- shoot other possible fixes over the phone, but call them out if necessary.

Burst Pipes

Freezing water causes obvious problems after a cold spell, and if a pipe or connection has burst it will be immediately apparent. If you see more than a few teaspoons of water coming from a wall or floor structure you probably have a serious plumbing leak.

  1. Turn off the water at the mains immediately, (there is often a valve under the kitchen sink, or at your water meter location which may require a special tool).
  2. If the leak is still flowing after the water is turned off, empty the water storage tank by running all the taps as an emergency measure.
  3. This will limit the extent of damage caused by the leak.
  4. Seek professional help

Condensation Effects which Look Like Leaks

It is also possible for condensation effects to occur in winter which can be mistaken for leaks from the plumbing system. An example would be when very cold water from an uninsulated water tank runs through a pipe inside a well heated home. A lot of condensation can form on such pipes from the moist, warm internal air. This can form in small pools or damp patches.

These issues can usually be solved, but appear intermittently so they can be hard to identify. You may need some input and investigation by an architect or surveyor.

Walls, Windows and Doors

New hairline cracks or any larger cracks in the plaster of load- bearing walls are a sign of underlying weakness in the structure.

Snow and ice are heavy. This weight can bend, tear and deform roofs very quickly, but it ultimately transfers the load through the walls to the ground. Pitched roofs should sit on top of the walls, and not push the walls outwards. If the roof is not built to resist “spreading” this can result in cracking in the external walls under a snow load.

This additional weight could also be the “straw that breaks the camel’s back” for latent wall and foundation defects, and could precipitate cracking due to underlying problems. If such cracks appear under a snow load, you need to consult a structural engineer.

Windows and doors may become blocked by ice, forcing them open could damage frames or draught- proofing.

Wasn’t My House Designed for This?

Yes, it SHOULD have been, particularly if it was built after 1990. As I have mentioned many times in this blog, Ireland has a massive legacy of what architects call “latent defects”. In short, there are many quality control issues in Irish buildings which go unseen, as a result of decades of loose certification and inspection practices during construction. These buildings may be adequate for day to day use for many years, but lack the full design strength and resilience their designers intended for more extreme conditions, which happen less frequently.

Common Defects An Architect or Surveyor Can Actually Check For

  • Mains water supply not buried at sufficient depth to prevent freezing, usually 600mm below ground level.
  • Water stopcock chamber not insulated
  • Water storage tanks and pipes not lagged and insulated, when installed in areas outside the heated envelope of the building.
  • Attics fully sealed and not ventilated (this leads to moisture build- up which allows timbers to rot)- check to ensure some daylight is visible in the attic
  • Fully sealed cold deck roofs; most low pitch roofs need constant ventilation to prevent rotting of roof timbers. There should be vent holes or small slits in the design of the roof eaves. You do not need this ventilation if your “flat roof” is a warm deck. An easy way to differentiate between cold and warm deck roofs is their thickness. A warm deck has a layer of insulation on top of the structural “deck”, whereas cold deck roofs place the insulation between timbers or under concrete slab decks. A timber- built cold deck is likely to be less than 300mm thick, a warm deck is likely to be at least 350mm. With concrete decks, it’s more complex but you can get a good idea by tapping the top surface to determine if the insulation layer is on top.
  • Missing roof straps to secure roof to walls. In traditional pitched roofs, you will see steel straps tying the horizontal timber “wall plate” to the external walls of the house.
  • Inadequate cross bracing due to amateur design or omission of elements during construction
  • Removal of roof timbers as part of amateur attic conversion processes
  • Insufficient fixings in slates and tiles
  • Wrong roof finish for the roof pitch or application.

Loss of Strength Due to Normal Wear

Roof structures also deteriorate over time in certain conditions, and as roof timbers rot, they loose part of their strength. Even if your roof withstood the snow of 1982, it could still bend, crack or loose slates after this storm.

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