In this document I have tried to give a step by step process how to do lay out Rat-Trap masonary.

1. Rat trap bond masonary
1. The first rule of starting any masonary whether exposed or not is to place all the units (bricks,
blocks, or stones) in the bond decided all over the plinth even covering the door openings.
Remember above the lintel there are in most cases no openings but masonary has to continue.
Here is a picture of a rat trap bond masonary in the starting phase.
2. Note there is a header course above the plinth. This course is like a leveling course since
sometime plinth may have exceeded the thickness. It also takes care of the chipping which
might be needed for fixing skirting. This header course if the plinth concrete has swelled up is
adjusted with stretcher and mortar if need be.
3. Above the header course you can see the beginning of rat trap bond which is a mix of headers
and stretchers with the gap due to the bricks having been placed 4.5” height.
4. This needs to be done on all over the plinth including the door openings. The same is to be done
without putting in the mortar between the bricks. It is a dry arrangement which will give you the
correct mortar thickness to be maintained throughout the building as well as avoid any small or
irregular brick sizes.
5. Laying of this course will also allow you to adjust the opening sizes if need be.

2. In this picture the large frame you see was adjusted as per the brick sizes.
6. In the picture below you can see the soldier course as well as opening. You can also note the
solider course below the window. Rat trap bond since it has a hollow it is best to close the same
at sill level.
7. If electrical points have been decided run a conduit in the hollows vertically- the best way to not
expose the same. Will have to fish out an old photograph but it’s plain common sense-place a
conduit vertically bring it to switch box height at a course level place an elbow. Place another
conduit with an elbow to continue the wiring to the roof/lintel level wherever the fixture is.

3. This picture shows some reinforcement but this is the way conduits too stick out.
8. In this picture you can notice as to why the whole bonding must be laid out as the first course
after the soldier course. Above lintel there is good clean bond continuing throughout.

4. 9. The t and cross junctions of the bond are available in Laurie bakers’ book. Here is the corner.