How to Choose the Perfect Wooden Stretcher Bar for an Already Painted Canvas?

You’ve just come back from vacation with a rolled-up painting, or maybe you've found a vintage gem, and you want to mount it on a wooden stretcher bar. The big question is: "What dimensions do I need?"

Whether it’s a travel souvenir or an old masterpiece, your painting canvas deserves to be shown off properly. But be careful: mounting a pre-painted work is different from prepping a blank canvas for painting.

As a long-time supplier of art supports, I’ve seen hundreds of DIY mountings. Here are my tips to ensure your canvas stays tight, straight, and—most importantly—to make sure you don't lose part of the artwork due to a measuring mistake.

1. Why the wooden stretcher bar is the skeleton of your artwork

The wooden stretcher isn't just a hidden frame; it allows the fibers (cotton or linen) to breathe and stay flat. If the stretcher is poor quality or the wrong size, your canvas will buckle as temperatures change. For a large format painting canvas, this is even more critical: you need sturdiness to counter the tension.

2. The Crucial Step: Measuring Right (Avoid this common mistake!)

This is where it all happens. To fix a canvas to a stretcher, the fabric must "wrap" around the wood to be stapled at the back.

The Expert’s Example Imagine you have a canvas where the painted motif is exactly 100 x 100 cm.
The classic mistake: Ordering a 100 x 100 cm stretcher frame.
The problem: Your stretcher has a thickness (often 2.4 cm or more). To cover the edge (the side) of the wood and staple it to the back, you need extra margin.
The Golden Rule: For a standard 2.4 cm thick stretcher, your physical canvas fabric must measure at least 108 x 108 cm.

The simple math: Stretcher size + (2 x wood thickness) + (2 x stapling margin of 1 cm) = Minimum total canvas size needed. If you don’t have these extra centimeters, you’ll have to "sacrifice" part of the painting to cover the sides, or worse, you won't be able to staple it at all.

3. Standard vs. Custom Wooden Stretcher Bars?

If your canvas doesn't fit into standard sizes, don't force it. A custom canvas setup deserves a precise support.
Standard bars: Cost-effective, perfect for classic international formats.
Custom wooden stretchers: This is affordable luxury. We manufacture the frame to the millimeter so it fits your painted area perfectly. This is highly recommended for large format stretcher bars that need crossbars or braces to prevent warping.

4. How to mount your canvas stress-free

Once you have the right support, place your artwork face down on a clean surface.
Place your wooden stretcher frame on top.
Fold the edges over, always starting from the center of each side (in a cross pattern).
Use canvas pliers if the fabric is very stiff, but go easy: an old painting can crack if you pull like a madman!

Summary

Choosing a canvas for painting or a frame for an existing work requires a bit of geometry. Never overlook those few extra centimeters of margin—they make the difference between a professional look and an artistic disaster.
Unsure about the dimensions? Measure your painted motif and the total size of your fabric, then contact us. We’ll help you decide between a standard format or a custom-made wooden stretcher tailored just for you.

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