Gate keeps: How big can the gap between my gate and gate post be?

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The gap between your gate and the gate post is important for a number of reasons.

The most obvious one is security. If the gap is too big, an outsider could be able to get their arm or tools through the gate and open it from the outside. You therefore don’t want this gap to be too big.

Another reason is aesthetics. A gate with too wide, too narrow, or uneven gap won’t look as aesthetically pleasing as one with a suitable and straight gap.

However, it is common that people have a gap that is a bit too narrow because it looks better. The problem with this is it doesn’t necessarily leave room for gate keeps or strike plates that go with your lock.

To help you make sure the gap isn’t too big or too small, we have made an overview of the minimum and maximum gaps needed for each of our keeps.

If you’re not sure what a gate keep is or why you need one, read our guide here.


Minimum and maximum gap size overview:

Product Min. gap needed between gate and post Max. gap recommended between gate and post
Strike plates 5 mm 15 mm

38 mm

50 mm

38 mm

40 mm

15 mm

25 mm


The maximum and minimum gap sizes

As mentioned earlier, the gap size is important for a number of reasons. If you have decided you want a keep or a strike plate fitted, you need to be even more aware as these might need a larger gap than if you aren’t having them installed.

Please see our table above for the minimum and maximum gap sizes between your post and gate depending on which keep/strike plate you have ordered:

Standard strike plates:

As strike plates are generally made from a simple metal plate fixed to the gate, the gap between the gate and post can be smaller. They require less room, but you have to cut or drill a hole to receive the latch. The minimum gap needed between the gate and post depends on the thickness of the strike plate of course. The strike plates we supply require a minimum of 5mm and a maximum gap of 15mm.


Gate keeps:

two part BSK Superlock gate keep with slam plate
The BSK Superlock keep from Gatemaster

Secure keep – BSK:

The secure keep from Gatemaster, the BSK, includes a slam plate for the post and a bolt support plate to be mounted on the frame. As you can imagine, this keep therefore needs more space than a strike plate.


To be able to fit the BSK on your gate, you will need a minimum gap of 38mm and a maximum gap of 50mm between your gate and post.


Gatemaster interlocking keep
The BSKS Interlocking keep

Interlocking keep – BSKS:

The interlocking keep has an extra slot in the side which fits with a protrusion on the other part. This way the keep interlocks when the gate is closed and is more difficult to pry open with crowbars. Just like the BSK above, the BSKS is installed between the gate and post and requires minimum 38mm gap between the two.

The BSKS has less tolerance for the fitting than the BSK as the interlocking features requires precision. We recommend not having a gap bigger than max 40mm for this keep.


Lock slam plate attached to grey metal gate
The BSKG gapless keep

Gapless keep – BSKG:

The Gatemaster gapless keep might look more like a strike plate, but the angled back part of the plate keeps you from opening the gate the wrong way. It is therefore a keep and not a strike plate. Due to the striking resemblance to a strike plate, the BSKG requires a smaller gap than the BSK and BSKS.

We recommend that you have a minimum gap of 15mm and a maximum gap of 25mm for this keep.


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