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L. Baker Norfolk
01493 753 288
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How to install the LS12 Mailbox into an existing wall

7 Steps to fitting your LS12 Thames postbox into an existing brick wall

LS12 Postbox being fitted into a brick wall

Step 1

Cut a hole in the front wall at the required height.

  • A = 407mm, the height of the side of the opening
  • H = 427mm, the height to the top of the apex
  • W = 299mm, the width of the opening


Cut border for recessed letterbox front

If the slate front is to be recessed into the wall the cut an 18mm border around the letterbox hole. The depth of the border should be the depth of required recess amount + 3mm. I.e. if the slate is to be recessed back 10mm then the border should be chased to a depth of 13mm.

Rear hole cutout in brick wall

Step 2

Cut a hole in the rear wall the size shown below.

  • A = 398mm, the height of the side of the opening
  • H = 418mm, the height to the top of the apex
  • W = 280mm, the width of the opening

Note The bottom of the rear cutout should be level with the bottom of the front cutout. The sides should be equidistant in from the front cutout.

Section of brick wall cutout
Exploded postbox

Step 3

Disassemble the containing box by undoing the 4 brass T Nuts with the 4mm Allan key.

Remove any threaded rods that remain fixed to the front casting and re-attach the brass T Nuts. Ensure the nylon washers remain on the threaded rods.

Apply glue to postbox

Step 4

On the back face of the slate front, apply a bead of glue suitable for exterior use. (such as No More Nails) 10mm from the. Also apply glue to the front of the containing box.

Assemble Thames letterbox front and postflap

Step 5

Align the slate front with the front of the containg box and push the faces together.

Use the four 50mm bolts, washers and nylocs to fix the faces together.

Note: DO NOT OVERTIGHTEN THE BOLTS as this may damage the slate.



Insert letterbox into wall

Step 6

Ensure that the rubber seals are properly in place and slide the inner sleeve into the cutout.

With the help of an assistant re-assemble the letterbox components together. Ensure the adhesive on the slate is in contact with the brickwork. See the exploded view below.


Support mailbox

Step 4

Ensure that the slate front is square to the brickwork. (It may be necsessary to loosen the nylocks and adjust the front before re-tightening the nylocs

Apply a support until the glue has set.

To seal the slate face, run a bead of clear silicon around the sides and top edges (not the bottom) between the slate and the face of the brickwork.

Also seal the top and sides between the brickwork and the letterbox sleeve on the back wall.



Exploded view of the Thames mailbox:

Exploded view of Thames mailbox

A) Pan head bolt (x4)

B) Letterplate

C) Slate front

D) Containing box front

E) Rubber seal (x2)

F) M6 Washer (x4)

G) M6 Nyloc

H) Centre sleeve

J) Nylon washer (x4)

K) Brass T Nut (x4)

L) Securing stud (x4)

M) Containing box back



Click here to return to LS12 Thames postbox 

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Lettasafe, Unit 4 MB Site,, Norwich Road, Norwich, , NR13 4EZ, telephone: 01493 753 288