Snow and extreme weather can cause problems in your house. A well maintained house can make it easier to sell at the right price in the future. Remember that the buyer of your property will have a building survey carried out. This is because of what is known as Caveat Emptor meaning Buyer Beware.

Sketch of a typical house

We are going to look at snow and the effect that we find it has on residential properties and particular their roofs and floors. We will consider in our experience the problems that can arise which we have seen when carrying out surveys of properties due to snow fall.

Snow is melting on the dormer roof of a modern house. How well is a modern house insulated?

We are going to look specifically at the problems and issues we have found with how snow affects the roofs of properties that we survey. We are also going to talk about experiences we have had with snow more generally and we will also advise you of any research that has been carried out in this area by learned institutes or bodies such as the Royal Institution of Chartered Surveyors (RICS), Building Research Establishment (BRE), we may even look at Wikipedia but we will not take it as gospel!

Snow on the roof of Victorian terraced properties

Snow is caused by a process called precipitation in the Earth's atmosphere. It creates crystalline ice so that snowflakes fall from clouds in granular form. It can vary in type i.e. (hard or soft and intensity). It all depends on the way the snow accumulates, the way it melts and refreezes and the rate at which it falls (it combines well with wind and rain making it even more dangerous).

Winter snow scene with field gate

Snow falls on land hills, mountains and rivers. Recently it has been said that the latter may increase the risk of flooding (Sky news). This also affects property and we discuss this in another article to do with April seasons. Snow affects human society transport buildings and infrastructure (Wikipedia).

In recent years snow has become more important in the news with winters becoming the coldest for 100 years (Daily Express), and in recent winters the snow has been inches deep (Daily Telegraph).

One of the main problems for buildings is that snow creates a load which has to be calculated when designing a structure. It creates strain on domestic roofs and walls and then melts which allows moisture to enter inside.

Most of the roofs that are most likely to be affected by snow are residential but it can affect commercial buildings too. If you are interested in problems that snow can cause in commercial buildings and other property matters then the following articles may be of help to you:

Heavy load of snow on roofs

can cause problems

One of the key implications snow has is to cause extra load and dampness in residential homes. For example if we take a high pitch roof the snow creates extra weight which falls down the slope due to reduced friction with the tile. Snow moves toward gutters meaning that loads are transferred elsewhere and the problem is passed on! This can even occur on flat roofs of a conservatory for example.

Heavy snow on roof of thatched boxed timber frame property

Secondly if snow sits on roofs for long periods of time it can lead to water storage tanks and associated pipe work freezing in roof voids which can then burst and cause flooding.

In some cases gas pipes outside a house or electrical wiring can also be affected. Snow obviously means that more heating is required and can often lead to shortage of supply in your area.

If snow sits on roofs it can melt and water can find its way in between roof tiles such as slate or concrete causing dampness in the upper rooms of your home. It can even find its way into brickwork which can freeze and eventually cause cracks on the face of the brick work which is known as spalling. In fact snow makes the problem worse which is originally caused by rain and frost.

If snow accumulates it can add to the problems of flooding that are occurring in parts of England as most weather forecasters are currently predicting. We have been on a variety of Surveys in which flooding has led to dampness in ground floor joists ( see survey findings below). This can lead to future decay and rot followed by expensive insurance claims (which we have found clients to have bad experiences with). However it is important to understand that snow can contribute to flooding!

Spalling brickwork

We have witnessed roofs that are high pitched or very steep on which we can see snow creeping into roofs via gaps in roof tiling. Alternatively we find that snow slides easily down slate roofs where it then becomes trapped in guttering causing it to come away from its positioning or alignment.

Snow can get into gaps in tiles

and cause dampness

In our experience the problems caused by snow have never been severe enough for us to recommend that the roof tiles or gutters are completely replaced! Indeed one roof we looked at should use preventative measures for snow, rather than repair or replacement, and just realign the gutters. Certainly this is far better than the proposal to use alternative roof tiles and replace the guttering and downpipes!

The biggest problems surrounding snow is the additional capacity that it imposes on a roof that can lead to deterioration of the guttering which we believe occurs due to the reduced friction between roofs and the snow. This causes snow to congregate at localised areas of the roof. This may be, for example, on the rainwater down pipe at the corner of a roof.

Gutters may need to be realigned after heavy snow

We would carry out two different types of inspection for snow on roofs and other parts of the building.

Firstly we would do a visual inspection both externally and internally.

Secondly, we could check with a damp meter to establish the condition of the timbers inside the roof.

This is really where wet rot occurs caused by the moisture of the snow. We can also check for moisture in joists using thermal imaging and or a similar damp test. We would also carry out a visual check of the utilities.

Snow on the roof

Damp in floor joists

Cycling to work or school in snow can be hazardous

The circles and ovals are a system that we use within our structural surveys and building surveys to highlight problem areas so that you are not left wondering what the problem is.

Icicles on a Victorian bay

In addition to this if the photographs do not explain the problem together with our survey report we also add in one of our own sketches such as the example that is shown here below.

Victorian bay window with no foundations