Common Renovation Pitfalls
This gallery of infamous renovation mistakes might help you avoid frustration and extra cost of buying the wrong products:

Countertops
For all but the simplest areas, your best bet when ordering kitchen countertops is to have them custom-made to fit the space available. Often the space isn't square, making stock units hard to adapt. The final cabinet installation can also vary from the plans, the back-splash is easy to forget and it is difficult to calculate the overlap.

You can minimize errors by having the manufacturer of the countertop (or the salesperson) do the measuring. Typically, the first step it to trace the size and shape of the countertop onto a piece of cardboard, which is then cut and used as a template for the actual counter top.

Kitchen cabinets
The most common problem with kitchen cabinets-whether they are stock or custom-made-is ordering the wrong size. This is one area where measurements taken by a professional can pay off. It's a good idea to take preliminary measurements before you go to the store then ask a store representative or your contractor do the final measurements. They may charge a nominal fee.

When taking your preliminary measurements, draw a detailed floor plan with dimensions noting window and door openings. The easiest way to get an accurate drawing is on graph paper. Choose a scale such as ten squares equivalent to a metre to simplify the math.

Doors
Every door has either a right- or left-handed swing. Unfortunately there is no universal "swing rule". Different manufacturers define this swing differently, depending on the type of door and whether you face the door from outside or inside. The confusion is so widespread, most stores have left- and right-handed doors pictured on their order forms.

One method that works most of the time is to stand within the opened doorway with your back leaning against the hinges. If the open door is to your right, it's a right-handed door; if it's to your left, it's a left-handed model. The only other way to avoid this confusion is to order a "blank" door that can be either a left- or right-handed model, but then you have to bore it yourself for the lock set and mortise it for the hinges.

Windows
Part of the challenge of buying the right size window is to master the various means of measuring. Windows for new walls attach to the bare studs, while replacement windows typically go within the existing window jamb. On top of that, not all manufacturers list window measurements the same way.

It may be a good idea to ask your contractor or store salesperson to measure before ordering. If you choose to take the measurements, note the width first, then height as well as the wall or jamb thickness. And, remember that casement windows swing sideways like doors, so they have the same left-vs.-right problem.

Sinks and faucets
Many homeowners don't realize that kitchen and bathroom sinks come in varying depths and widths. People often find that the sink looked deep enough in the store but not once it's filled with dishes!

Another common mistake is choosing sinks with the wrong number of faucet holes. Most are predrilled for specific faucet configurations although some expensive models have separate handles and faucet. Before you take out the old sink, measure the distance between the centers of the two outside faucet holes.

Tubs
Unless you're buying a drop-in or stand-alone unit such as a claw-foot style all tubs are right- or left-handed. This "handedness" determines which side the holes are on for installing the fittings. What's more, you can't simply turn a wrong-sided tub around-three of its sides are designed to attach to the wall. The fourth has a finished side, or apron.

Tile
Whether it's ceramic, marble, slate or vinyl tile, colour variations are the main problem when ordering tile. Be sure you order enough material from the same batch. On most jobs, add 10% for waste to the original square footage. If the tile extends into a hallway or other rooms use a higher waste factor of approximately 15% since there's more cutting involved.

Venetian and vertical blinds
Once you get these blinds up it can be nearly impossible to get them off so accurate measuring is essential. You will likely find your window is not perfectly square and this must be taken into account when ordering. Carefully measure the width of the frame across the top, middle and bottom, then order the smallest dimensions for inside mounting.

None of these steps will guarantee an error-free renovation but they will tilt the odds in your favour!