Flat Pack Furniture Assembly Tips: 10 Mistakes to Avoid

A careful setup helps protect panels, floors, fixings, and your patience. Use the product instructions as the final authority for every build.

1. Do not start before checking the final position

Measure the finished furniture and the room before opening every box. Check doors, hallways, skirting boards, ceiling height, and nearby power points.

Large wardrobes and storage units can be difficult to move once built. Assemble them close to their final position when the instructions allow.

Leave enough floor space to lay long panels flat. You also need room to turn parts without scraping walls or nearby furniture.

Use the cardboard packaging, a clean rug, or a moving blanket under finished surfaces. A hard floor can mark panels before assembly even starts.

2. Do not assume every box and fixing is there

Large flat pack items may arrive in several boxes. Match the box count against the order before starting.

Open hardware bags carefully and keep each group separate. Small screws, dowels, cams, and brackets can look almost identical.

Compare every part with the instruction list. Stop if a required panel or fixing is missing.

Do not replace a missing fixing with a random screw just because it fits the hole. The wrong length can damage a panel.

Keep spare packaging until the build is complete. Product codes and box labels can help when you need a replacement part.

3. Do not skip the instructions

Read the full instruction booklet before step one. Look for symbols, wall-fixing notes, two-person steps, and panel orientation.

Then return to the start and follow the sequence. Flat pack instructions often rely on earlier parts staying accessible.

Skipping ahead can trap a fixing behind another panel. It can also leave you dismantling finished work to correct one mistake.

Keep the manual beside you throughout the build. If something feels wrong, check the last completed step before forcing anything.

4. Do not mix up left, right, top, and bottom panels

Many flat pack panels look identical at first glance. The drilled holes usually show which face and direction the manufacturer expects.

Before fitting anything, compare hole positions with the diagram. Check finished edges, grooves, hinge holes, and drawer-runner holes.

Painter's tape can help on complicated builds. Mark panels as left, right, top, bottom, front, or back.

Remove the labels before final cleaning. This small step is especially useful when several panels have the same finish.

Never drill a new hole because the original holes seem wrong. First check whether the panel is reversed or belongs elsewhere.

5. Do not reach for maximum drill power

The supplied Allen key or a hand screwdriver is often the safest starting point. It gives better feel as a fixing becomes snug.

A powered screwdriver can save time when the manufacturer allows it. Use a low torque setting and the correct bit.

Avoid impact drivers for normal flat pack fixings. Their force can strip holes, damage cams, or crush softer board around fixings.

Start screws straight and turn them gently. If resistance feels unusual, stop and check the thread, hole, and part number.

Do not keep tightening after a cam or screw has seated. More force does not automatically create a stronger joint.

6. Do not force dowels, cams, or panels together

Parts should usually align without heavy force when the correct pieces face the right direction. Resistance is a reason to check.

Make sure wooden dowels are seated to the depth shown. A proud dowel can stop two panels meeting cleanly.

Cam fittings also need correct orientation. Follow the arrows or diagrams shown in the product instructions.

Use a rubber mallet only when the instructions and material suit gentle tapping. Never hit a finished panel with a metal hammer.

If a joint will not close, loosen it and inspect the parts. Forcing the joint can chip laminate or damage particleboard.

7. Do not fully tighten the frame too early

Some frames need a little movement while the main panels come together. Tightening everything early can make later holes harder to align.

Follow the manufacturer's tightening sequence first. Where the instructions allow adjustment, bring the frame together evenly before final tightening.

Check that shelves sit flat and side panels remain straight. Make small corrections before attaching doors, drawers, or the back.

Do not loosen safety-critical fixings against the instructions. The product manual always takes priority over general assembly advice.

8. Do not ignore whether the unit is square

A cabinet can look finished and still lean slightly. That small twist can cause doors to rub or drawers to bind.

Place the unit on a level surface while assembling it. Check corners before the final tightening stage.

For rectangular frames, compare the two diagonal measurements when the design allows. Matching diagonals are a useful squareness check.

Adjust gently before locking the frame. Do not twist a fully tightened unit into shape.

Test doors and drawers before moving the furniture into final use. Smooth movement is a useful final alignment check.

9. Do not treat the backing panel as decoration

Many cabinet-style units use a thin back panel. Follow the instructions closely when fitting it.

The panel can help keep some designs aligned and reduce side-to-side movement. Its exact role depends on the product.

Square the main frame before fixing the back. Check the panel direction, grooves, and fixing points first.

Use every fixing required by the manual. Missing nails or screws can leave the back loose or uneven.

Do not add extra screws unless the manufacturer allows them. Extra holes can damage thin panels or conflict with the assembly instructions.

10. Do not skip wall anchoring when the instructions require it

Tall storage furniture can tip when its centre of gravity moves forward. Drawers, doors, children, and heavy items can increase that risk.

Follow the restraint instructions supplied with the furniture. Use the fixing method that suits the wall type.

IKEA New Zealand wall-anchoring guidance says covered furniture should be secured to the wall. It also says wall hardware must suit the wall material.

If you cannot identify the wall type, get advice before drilling. Hidden wiring, plumbing, and unsuitable fixings can create bigger problems.

Never guess which anchor suits plasterboard, masonry, or timber. Follow the product and fixing manufacturer's instructions.

What to check when parts stop lining up

Do not solve a bad fit with more force. Work backwards through the last few steps.

Check these points first:

• Is the panel facing the right way?
• Are left and right parts swapped?
• Is the correct screw or cam being used?
• Is a dowel sitting too high?
• Is a cable, runner, bracket, or hinge trapped?
• Was a fixing tightened too early?
• Is the frame already out of square?
• Did the instructions require a second person for this step?

If the answer is still unclear, stop before drilling or modifying anything. A reversible assembly mistake is easier to fix than damaged board.

When two people make more sense

Some furniture is technically simple but physically awkward. Long panels can flex while one person tries to hold and fasten them.

A second person helps with large wardrobes, bunk beds, tall cabinets, long desks, and heavy bed frames. Follow any two-person symbol in the manual.

Two people can also help when a unit must be raised from the floor. Check ceiling clearance before lifting tall furniture upright.

Do not use a wall, door, or unstable chair as a temporary support. Set up the room so both people have clear footing.

Final checks before you use the furniture

Do one slow check after the last assembly step. Do not load shelves or drawers until the unit feels stable.

Check that:

• required fixings are installed;
• doors open without rubbing;
• drawers run smoothly;
• shelves sit correctly;
• the frame does not rock;
• feet or levellers sit firmly;
• required wall restraints are fitted; and
• packaging has not hidden a leftover required part.

Keep the instructions after assembly. They can help with adjustment, spare parts, moving, or later tightening.

Check the care instructions for any later tightening or adjustment steps. Follow the guidance for your specific product.

When it is worth booking assembly help

DIY makes sense for smaller pieces when you have time, space, and the right tools. Larger jobs can become awkward quickly.

Professional help can make sense for a large wardrobe, several units, a full-room setup, or furniture needing careful alignment.

It can also help when the room is tight or the unit needs wall anchoring. Send the product link before booking where possible.

Shore Home Repairs provides flat pack furniture assembly on the North Shore. We assemble common household units and quote before work begins.

You can also combine suitable assembly work with small home repairs. Send the full list so the job can be reviewed together.

For a wider guide to handyman scope, see what jobs a handyman can do.

Furniture tip-over safety video

IKEA's "Secure It!" video shows why furniture restraints matter. The video supports the manufacturer's current New Zealand wall-anchoring guidance.

Frequently asked questions