What material are they made of? What is your plan/methodology for permanent mounting? What material are you mounting to - siding, brick, etc.?

Al

Hi Al,

The boxes are mqde of cedar and they will be mounted against cedar siding. My only plan is to ask the person who will install my new windows (who presumably has carpentry skills) to mount them for me, however that's done, at the same time he's doing those windows.

From a longevity standpoint, you should arrange or insist on some sort mechanical method of supporting the weight from the bottom, even if the boxes are also attached through the back side that contacts the siding. I say this because it eliminates leverage on the fasteners holding the boxes together and transfers support to primarily sheer-strength of the fasteners through whatever mechanical support you choose - some sort of metal bracket or triangular arrangement of wood supports, most likely.

If you only fasten through the back side of the boxes, or even if you just use a cedar cleat that helps support the weight on the back side, any weight in the box (even if you use a liner) will have leveraged force against the fasteners holding the ends and bottom to the back. The box structure will fail prematurely at these points, even if glued and screwed.

I hope I was able to be clear enough & didn't confuse you?

Al

This type of bracket (click link) transfers the weight to fasteners that rely primarily on sheer-strength, supports the weight mechanically from the bottom, and eliminates stress and leverage against the fasteners holding the box together.

An alternate to this type of bracket, though not quite as strong: Attach a wood cleat to the siding to support the back of the box. Screw a 1 x 1 x .125 aluminum angle or a 12 ga. 1 x 1 steel angle (steel will rust & stain the siding eventually) through the face and bottom of the front of the box. Leave it a little long and attach a brass s-hook and brass chain to each end (brass eliminates the electrolytic activity you'll get with steel to aluminum & won't rust). Screw or otherwise attach the chain to the side of the building at approximately a 60* angle to the box bottom. This will also support the weight of the box and contents, and eliminate the leverage against the fasteners holding the box together. If you want to get really fancy, you could incorporate a brass turnbuckle into the arrangement to adjust/correct any sag that might occur over time.

Al

The thing to consider is that you are hoping for a permanent mounting solution for a not so permanent windowbox (wood). My two 10-yr old windowboxes (untreated and unpainted wood) lasted without care, but the exterior edging of one is rotting as all wood material will rot and need replacement or restoration work done eventually. The boxes don't have to be removed to be cleaned or painted, but if they need to be replaced or restored or be taken down for other reasons you may have more flexibility and less costly options if they are removable without doing damage to the siding or windows to the house.

Thank you Al and Legacy! You've given me a lot of help. I'm so glad I askd.