Common Install Errors - James Hardie Plank

With the UK's current climate, Hardie Plank can last longer than 30 years, keeping its beautiful exterior. That being said, to ensure this lifespan, its important that your builder or contractor follows all installation guides.

Here is a guide to the 9 most common mistakes made when installing our cement fibre cladding and trims.

• Ugly Touch Ups

By far, touch ups are the most common error, if a contractor uses too much paint on your cladding when covering nails or slight imperfections once installed, the touch ups will fade fast leaving your exterior looking like it has 'chicken pox'. The only way to fix this is to repaint the entire section or wall. The easiest way to tell if your builder/contractor is using too much Touch-Up Paint is to look at your house from multiple angles and in different light conditions. If 1 or 2 spots are 'shiny' and 'circular', they may not have painted correctly.

• Storage

The way you store James Hardie Plank Cladding is critical. We all know how fast British weather can change and therefore we don't recommend storing cladding outdoors uncovered for long periods of time. Store planks indoors or under waterproof wrapping, stored off the ground, a pallet is an ideal solution to keeping ground moisture away. Hardie Plank does a great job at drawing off moisture once installed on a wall but left uncovered and flat on the ground will help it absorb moisture. That being said, Hardie Boards can take lots of water so installing in light rain isn't a problem to worry about (if you don't mind getting wet!). If a board does become wet out of your control, leave it to dry out before installing.

• Butt Joints

Hardie Siding lengths are 3m long which means cladding on your longer walls need to join together. Although this is very simple, there are a number of ways builders can get this wrong. There is zero need to leave gaps between the boards when joining on a longer exterior wall, the boards should be touching each other when installed. We recommend when joining lengths together, you use a slip sheet behind to make sure that no water gets through. 

• Not Enough Pins

Unfortunately, some builders don't realise that Hardie Panels need to be fastened in a consistent pattern, with full-headed screws or pins. These boards weigh around 2.3lbs per sq. foot which means when the wind pushes them, they can flex slightly if they aren't properly secured.

• High Nailing

Hardie Siding has a nail line across the top of each board that is 1" down from the top, nails should fall between 3/4" and 1" from the top of the board to give the most secure yet discreet hold. Any lower and you may see a few nail heads popping out, any higher and your cladding may be loose.

• Clearances

James Hardie Plank should be installed with a minimum of 2" gap from all hard surfaces like decking and roofline and at least 8" from soft surfaces such as grass, gravel and mud. If you install your siding too high or low, it is likely that the boards will absorb moisture from the ground or roofing area, this can also lead to the paint on the surface bubbling or flaking.

• Ugly Caulking

No matter where your cladding meets a trim board, we recommend you leave a 1/8" gap between the siding and the trim and apply a 3/8" bead of approved caulking to protect and seal the edge of the cladding. Always remember to match the caulking to the colour of the siding, and not to the colour of the trim you are using. Keep in mind that some Caulking has a shrinkage percentage so we recommend using our Soudal Silirub LMN. Experienced cladding installers will know that messy caulking is the fastest way to ruin a perfect exterior.

• Cut Dust

You will know by now, James Hardie Plank is made of cement fibre, which means extra care should be taken when cutting. Make sure the installer doesn't breath in sand particles as continued exposure to this can lead to sever health issues. Once installed on your structure, there is zero health risk to home-owners from silica. Another issue is dust sticks to Hardie Touch Up Paint. This paint was well developed to stick perfectly to cement fibre, meaning if the builder doesn't wipe dust off instantly, it can start to settle and stick to the paint. 

• Corrosion Resistant Pins

Almost all nails, pins and screws have some sort of rust resistant coating on. Whilst James Hardie comes with a long warranty, you still need pins to last this long too. Galvanized or stainless steel pins are recommended but you can find everything you need here. The last thing you want is rust leaking stains on your cladding or even worse, your cladding falling off!