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How to Lay Bricks in Winter

March 6th 2018

How to Lay Bricks in Winter

When it comes to laying bricks, a slight chill in the air and the need for a light jacket is nothing to worry about. But, when the temperature starts to drop, and frost or snow is on the horizon, your brick laying process needs a little tweaking.

Laying bricks in cold weather presents a whole new set of challenges. Persistent rain, lingering frost and a cover of snow can turn a small job into an ongoing nightmare. Additional precautions need to be taken. While the simple solution is to wait until the temperature picks up, sometimes it's not that easy. If you have an urgent project that needs to be finished, read on to learn how to lay bricks in winter safely.

How Does Cold Weather Impact Bricklaying?

Cold weather can have a massive impact on your mortar. If you're unsure of what we're talking about, mortar is the cement that binds your brickwork together. It's typically made from a combination of sand and cement (and sometimes lime), which is activated by adding water. Extremely cold weather causes the moisture in the mortar to freeze and expand, compromising the structural bonds and waterproofing properties of the mixture. Discard any frozen mortar immediately. Avoid any anti-freeze agents too, as these not recognised within the U.K.

When mixing the mortar in sub-zero temperatures, the hydration rate is another concern. Cement takes far longer to become hydrated by water when mixed in cold temperatures. This means that your mortar will take longer to set and reach ideal strength. In some cases, it will not reach full strength at all, leading to a weak bond and a structure prone to cracking.

Storage and Protection of Materials

Storing your materials and keeping your finished or part-finished work safe from the elements is crucial. Before you purchase materials and get started on your project, take note of what you need, and make sure you have a dry, covered area suitable for storage.

Storage of Materials in Cold Weather

Bricks and mortar materials (lime, sand and cement) must be protected from frost and moisture at all times. A dry location such as a shed or garage is ideal for storage. Materials should be placed on a tarp or canvas sheet (to prevent moisture seeping in from below), in addition to being adequately covered.

Bricks should also be completely dry and protected from rain, ice and snow. Careful consideration needs to be made to ensure mortar does not come in contact with any frozen surfaces. In excessively cold temperatures, the bricks should be heated to prevent the temperature of the mortar lowering when it touches the brick.

Protection of Partially Completed Walls

If you've finished work for the day, or you have a break in construction, you need to ensure any partially completed brick structure is adequately protected and correctly insulated. A hessian blanket can be used to keep the heat in, although this will become useless if wet. Use a polythene sheet to waterproof the structure and prevent any damage from overnight frost or rain. Protective covers should be securely fastened and placed with a small gap between the masonry to avoid 'sweating' and smearing of the mortar. It's also important to realise the mortar can take longer to cure in cold temperatures, and in severe frosts, may require a heat lamp.

What Temperature Should I Worry About?

Temperatures lower than 4°C can compromise the structural integrity of your brick wall. According to the NHBC (National House Building Council), masonry construction should not proceed if the temperature falls below 2°C, unless suitable heating is available.

Temperature What should I do?
4°C and above No precautions or extra procedures are necessary.
Below 4°C Ensure all surfaces and materials are free of ice or frost. Heat water and sand before use. Insulation is needed for newly laid masonry. Mortar should be kept above 4°C.
2°C and below. Masonry construction should not go ahead unless appropriate heating is provided and mortar temperature can be maintained above 4°C.

Tips For Laying Bricks in Winter

Before you Start

  • Check the weather forecast regularly to ensure you are adequately prepared for cold temperatures. Assess the weather on the day, and if the temperature is planning to drop below 2°, it may be worth postponing the job. A minimum/maximum thermometer should also be used to determine if the temperature is falling or rising throughout the day.

  • Do not lay bricks in temperatures below 2°C, unless heating is available. Maintain mortar temperature above 4°C at all times.

  • Take wind chill into account. Wind chill can drastically reduce the surface temperature of newly laid masonry, compromising the mortar. Use windbreaks or enclosures to protect structures (and yourself) from the wind.

During the Job

  • Do NOT use any materials that have been damaged by frost or are frozen. Slightly wet bricks or blocks must be dried before use to prevent freezing. Discard any frozen mortar as the strength, and binding ability can be compromised.

  • Materials may need to be heated prior to use if it excessively cold. Sand and water should be above 4°C to produce mortar.

  • Protect all materials from rain, ice and snow at all times. If you must lay bricks during wet weather conditions, set up a protective tent that completely shields your working area from the rain. Follow all manufacturer recommendations for protection and handling.

  • Mix small amounts of mortar at a time to prevent way water from not be absorbed into the mixture.

Completed or Partially Completed Work

  • Cover any new and unfinished masonry work during winter with an insulating blanket (hessian), and a waterproof sheet (polythene) held down firmly on each side. Use heat lamps to maintain mortar temperature if severe frost is expected.

  • Ensure all protective covers are not placed hard up against the brickwork. There should be a slight gap to prevent 'sweating' and subsequent mortar smearing.

  • Stand back, admire your work and congratulate yourself on a successful project. Now, get inside and stay warm!

Take Additional Precautions When Laying Bricks in Cold Weather

Now you're equipped with the knowledge to get your bricklaying jobs done safely and efficiently, even on the coldest of winter days. Remember, anything below 4°C needs special precautions, heating measures, and covers for your bricks, mortar and hard work. Laying bricks in cold weather is challenging, but if the project must go on, follow these tips for a successful, strong, and long-lasting wall. Good luck and stay warm!