Penetrations through claddings need to be carefully detailed so they are weathertight. For commercial buildings, they may also need to be seismically restrained to prevent impact damage.
Timber weatherboards have an excellent performance history, and almost one in four new houses is clad with them. Using a good product with the right handling, installation and finishing procedures will ensure a quality job.
When combustible materials like timber are included in a façade system, the evaluation of vertical fire spread risk requires testing the system as a whole. There are several key things to consider.
Sometimes, gaps must be sealed, but in other circumstances they shouldn’t. The reasons are backed by science, so stick to these guidelines for a well performing building.
While the use of timber weatherboard cladding varies with changing trends, it remains perennially popular and its design and installation is well documented.
Although aesthetics are important in cladding selection, other factors need to be considered to ensure any water hitting the exterior is deflected, or can drain away or dry out.
Bevel-back weatherboards are back in vogue, but there’s a lack of experienced installers. This has led to some poor installations, so here are the key pointers to getting it right.
Current designs for both domestic and commercial buildings often have more than one cladding system. These can be tricky, so what is the best way to detail these junctions?
The home is built and now the timber cladding needs painting or coating. It is important that this is carried out correctly to ensure long-term durability and a great appearance.
House designs with brick veneer cladding at the bottom and weatherboards above present a design challenge. Here we have some details that allow ventilation and drainage from the upper cladding while preventing additional moisture entering from the brick cavity and maintaining ventilation of the veneer cavity.
Vertical board and batten as a cladding reaches back to the earliest days of New Zealand settlement. The memory of rough pit-sawn timber and the scale and familiarity remains and many owners find it appealing, so the use of board and batten continues to this day.
The back of brick veneer will get wet when it rains. That’s why it’s important to design in elements such as vents and open prepends, install the veneer following the correct practices and adhere to certain tolerances.
Some external moisture is likely to penetrate masonry veneer, but this isn’t a problem when sufficient ventilation can drain and dry any water that enters. In this example, poor construction details restricted ventilation and caused problems.
Horizontal timber weatherboards have been a popular cladding material for houses in Aotearoa New Zealand for many years, with an excellent track record for durability when properly installed and maintained. Even when maintenance has been less than ideal, timber weatherboards have sometimes lasted more than 100 years.
Using longer and thicker nails to fix horizontal timber weatherboards to structural framing through cavity battens can damage the weatherboards. However, there’s a way round this.
A Build reader recently asked if H3.1 treatment for timber cladding is sufficient to protect against rot. It is, but only if primed before installation, painted and regularly maintained.
University of Canterbury (UC) has been researching the flammability of timber building envelopes – part of an MBIE-backed programme into wildfires and their impact on communities.
The occurrence of wildfires is growing and is no longer only the concern of fire services. Designers and builders must start thinking now about the houses they construct and how resilient they will be in a world of increased fire risk.
A preliminary BRANZ study into the fire performance of hollowcore concrete floors suggests that conventional fire design requirements for precast floors may need to be reviewed.
Calls to the BRANZ helplines have revealed confusion created by differing advice in NZS 3604:2011 on the ground clearance needed for particleboard flooring. What is the ground clearance needed?
Part 2 of this Build series on designing and building medium-density housing covers inter-tenancy floors. The most important consideration here is to eliminate penetrations into the inter-tenancy floor zone.
The BRANZ Technical Helpline often receives queries for designing and building suspended timber floors and dealing with uplift. Nine of the most common questions are answered here.
All timber floors deflect to some degree under load, but a floor that deflects too much when walked on can be disconcerting. Floors rarely fail, but a bouncy floor often indicates a problem with the floor joists.
Lessons from the Canterbury earthquakes mean that all concrete floor slabs must now be reinforced with steel bars or welded mesh with a reasonable degree of ductility.
In Build 188 Keeping in character, i looked at the major structural issues confronted when refurbishing Aotearoa New Zealand period and character homes. In this third article in the series, i discuss the internal fit-out and what you may encounter.
Timber floors are aesthetically pleasing, but over time, they can become scratched and damaged. To keep them looking good requires ongoing maintenance and repair.
Look up our experts and connect with trusted building science specialists who can provide practical advice, technical insight and evidence‑based guidance to support your research, project or decision‑making.
A research project found the practice in Aotearoa of seismically compatible detailing does not always improve the fire performance of a beam-column joint compared to joints designed without it, as occurs overseas. One answer for better fire performance may be to look at British fire performance practices.
As the push for more timber construction continues because of its low carbon attributes, further research into the fire safety of timber products is important. Recent BRANZ projects added to the available knowledge.
Designers need to show that heavy timber buildings maintain their stability during and after a fire. A joint research project has initial findings on the fire performance of mass timber construction joints to help.
The growing prevalence of mass timber construction in buildings, allowing larger compartments with larger openings, presents new challenges for fire safety designers.
