<p>I'm trying to print with Laybrick and for the most part it is going.  The problem lies with the top layer and gaps appearing.  I've tried increasing the number of top layers but the gaps still appear.  Any ideas what else I can try? </p>

<p>I'm using Simplify3d.
<a href="https://i.stack.imgur.com/Y05dR.jpg" rel="noreferrer"><img src="https://i.stack.imgur.com/Y05dR.jpg" alt="Image"></a></p>

When using Simplify3D, you may try referring to their awesome troubleshooting guide:
https://www.simplify3d.com/support/print-quality-troubleshooting/#holes-and-gaps-in-the-top-layers
3 reasons (from the guide) for gaps in the top layers:
under-extrusion: you may try to increase extrusion multiplier to see if this helps
low infill percentage: not likely in your case if increasing number of top layers did not help
not enough top layers: you already tried increasing number of top layers.
In addition to that, you may change certain parameters (such as extrusion multiplier) for a given number of layers by using Simplify3D features. It can be helpful to avoid problems to for the rest of the model.