Recurring Stability Issues with Brick Piers

[Hydro2340]

Hi everyone,

18 months ago I had two front garden walls built with reclaimed London Bricks. There are six piers along the two walls. Three of them have already had their top layer of bricks come loose and are not properly fixed to the main wall anymore (they wobble but are held in place by the railings).

The pier which holds the gate post has an iron bar in it (see photo), which makes it more solid, but even that isn't properly attached to the lower wall anymore (held on by railings though).

Any advice on cause/how to rectify would be much appreciated. Some of the piers have been rebuilt two/three times and it keeps happening - the builder is flummoxed

Cheers

 

[Harry Bloomfield]

Rebuild it with some steel reinforcing in the mortar joints.

 

[stuart45]

9 inch piers are too small

 

[tony1851]

If the builder is flummoxed as to why that keeps happening, he needs to get a different job.

 

[robinbanks]

Perhaps your black railings are expanding in the sun and shoving the piers sideways. Incorporate some ability for them to slip on the mounting brackets and see if your piers still come loose

For example, have an L shaped bracket onto which the railing is loosely bolted:

 

[mrrusty]

Thermal coefficient of expansion is 0.012mm/m/deg so 3m of steel in a temp range of 30 degrees will expand and contract about 1mm.

 

[stuart45]

You need a minimum pier size of 1.5 bricks for railings. You could lean on a 1 brick freestanding pier and it would fall over.
LBC Flettons as a brick on edge don't usually last that long.

 

[bernardgreen]

What mixture did the builder use for the mortar ?

 

[Hydro2340]

Thanks everyone, this is already incredibly useful.

What mixture did the builder use for the mortar ?

He was a bit outraged when I question him on this - "the same one I've always used and it's never done this".

Perhaps your black railings are expanding in the sun and shoving the piers sideways. Incorporate some ability for them to slip on the mounting brackets and see if your piers still come loose

Thanks, this is a really good idea. I still think piers wouldn't hack the weight though as the railings are pretty heavy. The only pier that is still solid is the one cemented onto the neighbour's wall.

Thermal coefficient of expansion is 0.012mm/m/deg so 3m of steel in a temp range of 30 degrees will expand and contract about 1mm.

So rather than the expansion and contraction it could just be their weight maybe?

You need a minimum pier size of 1.5 bricks for railings. You could lean on a 1 brick freestanding pier and it would fall over.
LBC Flettons as a brick on edge don't usually last that long.

Thanks Stuart, as well as changing pier size, do I need a pier cap? Or would you say LBCs shouldn't be used?

 

[freddiemercurystwin]

You need a minimum pier size of 1.5 bricks for railings.

This.

Google 'railings in brickwork' or similar, you will not find any piers as slender as this. Two bricks ideally.

 

[mrrusty]

So rather than the expansion and contraction it could just be their weight maybe?

1mm movement if bolted up tight will crack mortar joints.

 

[Hydro2340]

Thank you so much everyone for your detailed responses.

Any clever ideas for salvaging the current railings? We have realised they're classed on some sites as "heavy duty"; the frame is 40mm x 8mm and the infill bar is 15mm diameter.

Our options are between:
Losing the middle pier, rebuilding the end piers as 1.5 brick and perhaps adding a supporting post? Do these make any difference to stability
Rebuilding all three piers as 1.5 bricks and getting railings cut down so less weight?

We will ask the railing manufacturers to switch the ends so they can be fixed with the L shaped bracket/bolt system as per @robinbanks suggestion

Example of supporting post:

Grateful for any more wisdom, thank you.

 

[robinbanks]

Incidentally; the railings pictured in your "example of a supporting post" post do already seem to have the L bracket system I was describing

..and you'll note they also have pillars that are considerably larger than those you're struggling with!

 

[wessex101]

The damage appears to be restricted to the brick on edge copings and one brick but all above the level of the railings so I cannot see that the railings are the cause.

Looking at photo 4 it would seem that the bricks did not bond to the mortar. If the brickie is claiming the mortar mix is good then something must have happened at the time of laying to ****** the cement such as a heavy frost or a very hot weather? As it is just restricted to the coping bricks I would suspect the latter.

EDIT: the word censored is ret@rd ........ WHY?????

 

[freddiemercurystwin]

I would say the most practical and reliable way of getting a sound wall is to do away with the railings, rebuild the piers the same size they are and either just lose the railings or replace the railings with a single skin of brickwork tied into the piers with some frame ties, perhaps add a little grey coping on top or something. You can't practically rebuild the piers bigger without making the whole wall (at the piers) wider - may as well just start again.