How to fix a loose brick?

[tinnews]

This may sound a rather silly question but still....

I have built a little structure to enclose a pond filter, pumps etc. It's of straightforward brick and cement construction.

One of the top corner bricks has come loose (as a result of using an SDS drill). Is there any glue or similar that I can use to fix it back in place? I know I could chip the cement away and re-cement it but that seems a bit laborious and there is also the risk of loosening adjacent bricks. It's such a perfect fit in its place that it seems like some sort of fairly weak glue would do a reasonable job.

[The Natural Philosopher]

You can get epoxy mortar..but frankly I'd use brick acid to clear the mortar and redo it.

[Stuart Noble]

Car body filler. Remove some of the mortar to make a bit of room for it. Used it many times when gate fixings have broken the mortar on brick piers.

[Steve Firth]

I would recommend the use of a foaming polyurethane glue for this. I've had similar problems when restoring a rubbed brick arch where it was impossible to "butter" the lime mortar onto the brick and get a good fit afterwards.

After much negotiation with the LBO we got permission to inject polyurethane glue and this made an invisible repair. The advantage with PU glue is that it is transparent, and that it reacts with moisture to set and in the process begins to foam. This forces it into crevices and makes a good bond.

You need to secure the brick while the glue sets and to make sure that you don't use too much glue or the pressure of the foam will force the brick out of position and cause glue to ooze onto the face of the brick.

You can remove excess glue while it is soft using acetone.

Suitable PU glue can be obtained from Screwfix at a reasonable price, sold in 310ml cartridges.

[dg]

Use clear (or any colour) silicone or Gripfill.

dg

[Staffbull]

Yep, I'd go for gripfill (normal green tube) used it to stick back some copings I knocked off the garden wall with a mini digger while digging some foundations.

[Steve Firth]

It doesn't work reliably, Gripfill does not adhere well in the presence of moisture and it doesn't work well in the presence of dust or loose surfaces. In short both Gripfill and silicone have the same limitations as mortar and in the case of Gripfill one further drawback, the need to be used on dry construction.

[Stuart Noble]

None of these things will take where there's a layer of dust, but it's usually pretty easy to work the dust in when you apply it. Body filler would be my choice as it has a density more akin to mortar when it sets

[tinnews]

Thanks for *all* the replies, very useful. I'll be trying one or more in a few days time.

[Phil L]

Use builders PVA, unibond or similar, apply neat to both (dust free) surfaces and put the brick in place, wipe off any excess glue with a damp rag, it'll never move again.

[marvelus]

I knew someone would say to use PVA. Well I wouldnt use PVA for bricklaying.

[Phil L]

I PVA'd the corner of a coping stone back on after I'd hit it with a wheelbarrow, I didn't expect it to work but it still there now, despite being on a corner and getting more wear and tear than other masonry in the wall. This was in 1983 BTW

[The Natural Philosopher]

Yup. Funny stuff is PBVA. I had some scree laid pretty badly, and a join between tow days cracked, and sounded 'hollow' on one section..and moved under pressure.

I poured half a gallon of PVA into the crack, and a week later it was as solid as a rock.