How exterior walls are put up

 

[caption caption="How fast the walls go up will depend very much on the materials being used." align="right"]  

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Once the frame's up (and sometimes after the roof goes on), it’s normally time to put the external cladding on your house. How exactly it’s done will depend on what you’re building with. Obviously the process for cladding a house will be different depending on what you’re using – bricks, weatherboard, metal cladding, hardboard or something else – and the amount of time it’ll take will vary too.

How bricks are laid

Bricklaying's a relatively slow process, but watching a proficient brickie at work can be completely hypnotic. Bricks need to be laid evenly and with the right amount of mortar in the right spots - and there are a few different mortaring techniques (which you can often specify when you're planning your home).

Some people might actually be surprised to find that a brick veneer is pretty much just that – a ‘veneer’. It doesn’t hold any of the weight of the roof – it’s there to provide a protective and decorative outer shell.

Brick walls do a pretty good job of keeping wind and moisture out though, so there’s usually little need for sheathing between the building frame and the bricks. That said, brick is also extremely porous, so it is important that a consistent ‘cavity’ is maintained between your brick veneer and the frame to prevent any water damage.

Brick walls are attached to the frame at various points using galvanised steel brackets called ‘veneer ties’. These help to maintain the cavity between the bricks and the frame, to make the frame a bit more rigid, and to help to add support against the force of the wind on the walls.

Damp-proof courses

The exact details of how your brick cladding’s done might differ slightly from house to house, but most brick walls are built with a damp-proof course near the bottom of the wall, in accordance with Australian Standard AS/NZS 2904:1995 'Damp-proof courses and flashings'.

A damp-proof course (or DPC) is a barrier made of plastic or bituminous aluminium sheeting, which goes all the way through the bricks. The damp-proof course is designed to prevent moisture from entering the building. In homes with a timber subfloor, the DPC is normally put in two courses (i.e. two rows of bricks) below the lowest timber member. In slab homes, the damp-proof course is attached to the frame and run down through the bricks just below what’s known as the ‘weep holes’. Weep holes are there to allow for drainage and ventilation.

In addition to a damp-proof course, things like vermin barriers and ant strips are also likely to be installed to help protect your home from unwanted visitors. Likewise, flashing is used around door and window frames to help prevent water damage. There's quite an art to bricklyaing, including several different ways to lay and finish mortar, as well as many different decorative techniques which we won't get into here.

Weatherboard, aluminium, hardboard etc.

How the exterior of the house is clad will depend as much on they type of cladding used (and its properties) as it does on the climate where you’re building and how the house is designed. Most houses using the types of cladding listed above will first use a layer of reflective foil laminate (RFL) sarking (or ‘wall wrap’), and flashings for where the cladding is affixed to the frame, or to openings for windows and doors.

Sarking used in walls is designed to keep water out, but also to be ‘breathable’ so that it allows water vapour through. This helps to protect your home from water that might penetrate through the exterior cladding, whilst also allowing vapour from inside your home to escape. It’s important to note that sarking isn’t supposed to be the primary defence against pelting rain and weather – that’s the job of the external cladding.

Sarking’s merely there to provide a secondary defence should there be any failing with the external cladding you’ve chosen to use. How exactly your external cladding is affixed will depend very much on the system being used – there are countless variations and means of affixing wall claddings.

How long does it take to put up the exterior walls?

Again, there's no easy answer to this question. Brick laying can take anywhere from a week to a month or longer, depending on:

• how big the house is
• the weather
• how many bricklayers are working on it, and
• how well they know their trade.

Other forms of cladding (like weatherboard and aluminium) are normally considerably faster and may easily be done in the space of a week, or even a couple of days.

Who works on putting up exterior walls?

• Bricklayers
• Carpenters
• Builders