Being the heat loving creatures we are, its natural to think that all building projects should take place during the warm, sunny months of the year.
Its true that there may be some additional hurdles to building in colder, wetter weather but with careful planning and flexibility there is no reason why you should wait for the weather to warm before getting underway with your new build or renovation project.
This month discuss some unique building considerations around construction projects during winter and some of the inventive solutions to keep your project on track.
Foundations and Concrete
Foundations and concrete are a vital part of any build regardless of weather conditions and the weather forecast will be your best friend. Concrete companies are experts in their field and will give great advice alongside your builder.
Thankfully, the New Zealand building code is very helpful in laying out a clause which defines unfavourable conditions for concrete pouring. Section 7 clause 7.2.1 stipulates that concrete should not be poured onto frozen ground or be poured in conditions that will be detrimental to the quality and finish of the concrete. Daytime temperatures below 5 degrees on a falling thermometer or when the concrete can’t be finished adequately.
Concrete companies will often use a low slump concrete which has a lower water content. They can also include additives and use a higher grade concrete with more cement content which will also set faster. Your builder can also use heat and insulation which will help the concrete harden and cure without vast temperature changes that will affect its strength.
For buildings with 100 mm thick concrete floor slabs, there is approximately 170 litres that has to dry from the slab for every square metre of floor area when it is poured. One week after the pour, this will have reduced to around 110 litres/m2. Under good drying conditions, the drying of remaining moisture so that the floor is dry enough for tiles or vinyl to be laid will take at least 4 months.
If you are building with a timber frame the maximum amount of moisture permitted in the timber at the time of lining the walls is 20% (GIB products suggest 18% maximum) It is likely that kiln‐dried timber framing will get wet during construction, and the timber will take up some of that moisture. When this occurs, time must be allowed for the frames to loose the absorbed moisture – how quickly will depend on the stage the building is at and the weather conditions after the rain. Drying will be quicker if it is windy.
The moisture that will be present, plus that added by rain, will need to be managed primarily by allowing as much air flow as possible through the building – once the cladding is installed, windows and doors need to be kept open during the day. Using heaters and dehumidifiers may help dry the air within a building when windows and doors are closed and assist removal of moisture, but its also important to bear in mind that forced drying of materials tends to just drive the moisture away from the surface (which may temporarily lower a moisture content reading) and not actually remove it. Allowing sufficient time for the moisture to evaporate is a key factor.
One product that we at Kit Markin find to be game changer for winter building is RAB® Board which is a 6mm solid fibre cement pre cladding that is mostly used for commercial builds, and residential builds exposed to extra high (EH) wind zones.
RAB Board provides superior weather-tightness, because its has a water-repellant sealant that prevents moisture getting in. The breathability properties of the RAB Board also allow for moisture vapour to get out. This means the timber moisture levels are reduced.
Because RAB Board is solid and more weather-proof, the building is able to be closed in faster and work can get underway on the inside.
In addition to the weather proofing qualities of RAB Board, it provides extra strength because of its rigid cement fibre board construction along with extra noise proofing and pressure equalisation for high wind zone areas.
For winter building this gives more flexibility with managing your build, and you can save valuable time and cost on the job.
If you are planning a new build or large scale renovation where the majority of work will happen over the winter – you are planning well in advance anyway, so its a good idea to collaborate with your builder about how to stage the building work to take advantage of good weather conditions. Just like the team at Kit Markin Homes, your builder will be able to give professional advice about how to make your build run smoothly with a minimum of down time, despite the more unpredictable weather in winter. Use of large scale coverings, speciality products, heating and insulating products will all help keep your build dry and warm and allow for work to progress.
Building anytime of year can be unpredictable, especially with New Zealand weather conditions, so flexibility and good forward planning are key.