Installing a door might seem straightforward but getting it right from the start can save you time, money and headaches down the track. Whether you’re working on a new build or a renovation, the way you prep, finish and install a door has a big impact on how it performs long term, and whether it meets warranty conditions.
Here’s what you and your crew need to know to get the best result every time.
Step-by-step: how to prepare a new door on-site
1. Inspect it on delivery
Before you start, check for any damage, confirm the door is square, and double-check you’ve got the right product for the opening.
2. Sand it back
Give raw timber a light sand to smooth out any roughness and help the paint or sealer stick. Wipe it clean before finishing.
3. Seal every surface
Use a quality primer, sealer or paint to coat the entire door: front, back and all edges Painting the edges of the door before you install ensures they can be adequately covered. A good tip is to lay the door flat while painting to avoid drips and runs and make sure you apply at least two topcoats over primer for full protection (always follow the instructions on the paint label).
Skipping these steps can void the warranty and cause moisture problems.
4. Choose the right finish
If the door is going external, use an exterior-grade finish for long term protection. Semi gloss or satin finishes are recommended.
5. Choose the right colour
Avoid painting timber doors with a low LRV (light reflective value), as they absorb heat and increase the risk of warping.
6. Let it cure properly
Give your paint or sealer the full cure time before the door is installed. Rushing it can lead to damage during fitting or early finish failure.
On-site install tips for long-term performance
- Allow for correct clearances
Fit the door with even gaps around all sides as per manufacturer specs. Tight clearances can cause binding, while too much movement opens the door to draughts and water ingress. - Use solid hardware
Stick to quality hinges and screws. Cheap gear wears out faster and puts stress on the door and jamb. - Provide some cover
For external doors, a small overhang or awning can make a massive difference to lifespan. Keeping the door protected from sun and rain helps maintain the finish and avoids moisture issues. Doors that do not have adequate overhead protection may void door warranty.
Keep it in good shape over time
After install, a quick check every few months can help prevent issues. Touch up any scratches or bare timber. Keep hinges tight. If you spot early signs of wear, act fast – it’s easier to fix problems early than replace a door later.
Do it once, do it right
As a builder or trade, you know time is money. Prepping a door properly before installation means fewer call-backs, happier clients, and long-term peace of mind. Seal every surface, use the right finishes, and follow manufacturer guidelines – and you’ll avoid costly rework and keep your projects on track.
Got questions about door selection or installation? Speak to your local Dahlsens team. We’ve got the brands, products and advice to help you get the job done right.