Bedding beam on brick wall

[jcp]

Our chippy has chocked up the ends of the double beams (2 of c24; 170x47mm, bolted together) around our new stairwell with a short small softwood wedge (about 30mm wide) banged in between the middle of the beam pair and the next brick below in the supporting internal brick walk. He has now gone off site in a huff with the voids around the beams unpacked. An unavailability of cement might be to blame!

I assume the voids should be filled with mortar, or the beams could surely move. Should I ram in a strong dry mix of cement and sharp sand (1:3, like I did between steel beams and in situ cast concrete padstones in earlier projects)? Or are there different rules for restraining timber beams?

The chippy had earlier said new rules meant he shouldn't really bed timber beams on possibly damp masonary walls, but this was unavoidable in our case. I am concerned the bearing surface of the timber wedge is very small, and could easily be compressed or dislodged.

I would be grateful for any advice.

 

[tony1851]

Timber beams don't usually carry much weight, so a small bearing area of wedge is unlikely to be a problem.

Just pack the void with a 1:6 cement:sand mix. As the mix dries out, it will shrink very slightly, opening up a small gap around the timber, but that will be of no consequence.

There are no 'new rules' about bedding timber beams into damp walls - that's always been bad practice. In these cases, the ends of the beam are usually wrapped with a dpc material stapled on.

 

[jcp]

Thanks for those comments.

The design load on the trimmer “double-beam” is just under half a tonne, so that’s just over 200kg on each bearing end - but in practice I doubt that even half of this load will ever be reached.

The wall is actually the inner skin of a cavity wall, but there is a 2m wide “flying room” over this, and the outer skin does not get rained on. I don’t think it can be described as a damp wall, and the beam end has not been wrapped in dpc material. The building inspector made no comments about it when he visited.

I am more concerned about the wedge being displaced (e.g. under vibration). I wanted to be sure that mortaring in the beam was the correct thing to do. I don’t think this could cause a significant moisture path to the timber, but I didn’t want the building inspector to ask me to remove the mortar on a later visit.

I feel happier to mortar it in now, so thanks for your help.