Renovation & Design

ASK THE INSPECTOR: Gap in kitchen backsplash can have several causes

QUESTION: Our kitchen counter backsplash has pulled away from the wall. It has pulled away on the two exterior walls and a smaller interior wall to about a quarter of an inch. What should we fill it with?

Thank you, Diane Zakala.

ANSWER: I regularly see homes, often newly built, where there is a gap between the top of the kitchen counter backsplash and the wall behind. There are a few reasons that this may be happening, and identifying which one is causing your problem is the key to determining the type of repair you should do.

The most common reason for a gap like this is improper installation. This may simply be poor securing and caulking of the counter itself, but it's just as likely an issue with leveling and fastening of the base cabinets below. The majority of modern kitchen cabinets are made in modular fashion from some form of particleboard or fibreboard. That means that a row of base cabinets is actually several individual units secured together.

Once assembled and connected, normally with short wood screws, the base units must be levelled and squared before fastening to the walls behind. The simplest way to level base cabinets is with thin wooden shims inserted at the bottom of the cabinet gable ends and at the back of the cabinets. If these shims are improperly placed, or if the base cabinets are not level, plumb and square after securing to the wall, movement can occur.

Since kitchen cabinets support a variable load, both on the countertop and in the shelves and drawers, some movement can occur. This is only increased by constant opening and closing of the doors and drawers.

If the cabinets are not held in place with the proper number and length of fasteners, they can pull away from the wall. As they become loose and pull away, the countertop will move as well. If this is the situation in your home, re-levelling and squaring the base units before installation of additional fasteners will be required before dealing with the gap behind the countertop.

Fitting and securing of the countertop, especially common post-formed laminate counters, can be a tricky task for those inexperienced with this type of finishing work. As we all know, walls in homes are never perfectly straight, square or plumb. This is due to variances in individual wooden wall studs, drywall seams and other normal construction materials. Particularly in older homes with plaster walls, there can be considerable bowing or waviness in the kitchen walls.

Installation of a perfectly straight countertop on a crooked wall, or walls, is impossible without modification. It's much easier to trim the backsplash on the countertop to fit the wall that the other way around. This may involve the use of a portable jig saw, belt sander or other less-modern woodworking tools. An experienced installer will order the countertop cut roughly to the angle of any corners and then scribe and trim the backsplash tight to the walls before fastening to the base cabinets. This can also be true of granite, stone or cultured-stone counters, but on-site modifications are much more difficult.

The other possibility for the gap behind the backsplash is due to shrinkage in building materials in the kitchen. While it's unusual for most countertop materials to shrink noticeably, some cabinets or wooden shims may get slightly smaller as they age. This can cause small gaps in some areas, but not normally as large as yours.

A more likely scenario is shrinkage or movement in the floor or wall framing in the kitchen area. If your house is newer and the floor is built with conventional framing lumber, there can be significant shrinkage in the joists and wall studs across the width of the boards. In typical two by ten joists, this can be as great as three or four millimetres.

That much reduction in the size of the joists can cause the base of the cabinet to drop, while the back remains relatively well secured to the wall studs behind. This could easily account for the space behind the counter in your home.

Floor settlement or movement at the main beam and teleposts could also account for movement in the base cabinets. This type of movement is very common in our area, due to our expansive clay soils, which may be the problem if your home is older but has a newer countertop. The last couple of summers have been very dry, creating above-average settlement and movement in many homes.

The solution to that issue is slow, careful adjustment of your teleposts, to try and return the floor structure to near the original position. In that case, you would not want to fill the gap at the backsplash, as it could be used as a guide to determine if adjustments are working.

Whether the space behind your kitchen countertop is caused by poor installation or movement in the floor or cabinets, filling a gap as large as yours prior to repairs will not be fruitful. Determining the exact cause for the movement of the counter before proceeding will be necessary. The repair will likely involve shimming and re-securing the base cabinets, and possibly the countertop itself, which may be critical to preventing a quick return of the void.

Once things are brought closer together, a simple bead of silicone caulking should do the trick to prevent water or debris falling behind the backsplash.

Ari Marantz is the owner of Trained Eye Home Inspection Ltd. and the President of the Canadian Association of Home & Property Inspectors - Manitoba ( Questions can be e-mailed to the address below. Ari can be reached at (204) 291-5358 or check out his website at



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