Advice on gluing an external concrete sill

[catrionag]

Hiya BuildHub - I'm after a bit of advice on gluing a concrete sill onto blockwork at DPC level - and this is the kicker - underneath a door that's already been installed.

 

A bit of background is that there were some timescale and communication issues between the brickie and the kit-builder (who is on site currently) that meant the windows needed to be installed before the sills - obviously not ideal on either side. It was agreed (reluctantly on both sides) that the kit-builder would install the windows with a 75mm packer, so that the 75mm sills could then be slid in afterwards - the foreman and the groundworker talked about this and verbally agreed on using glue for the sills.

My groundworker is great, but the brickie he subcontracted made an utter dogs dinner of it. He mortared them in, but obviously the 75mm gap wasn't enough for a 75mm sill + mortar, so he cut the blockwork down past DPC level to get them to fit. On two of the three doors, this is semi-acceptable as they could be either dropped or packed, but the main accessible entrance can't be dropped, and there is now too much of a gap between the bottom of the door and the sill - bigger than the 15mm required from NHBC.

 

My groundworker has told me that he cannot find anyone willing to glue these sills - apparently everyone wants to mortar them. So, long story short, I am asking him to come in to rebuild the Blockwork to DPC and then we are going to glue them in ourselves.

 

Can anyone recommend a glue, and are there any tips for making it easier on ourselves during the install process? I was thinking of using Adiseal and then pointing it up afterwards (the sill is three separate blocks). Any tips on good pointing would also be gratefully received because the original brickie managed to bollox that up as well and now it has to be redone on all of the sills.

[markc]

OB1 should do the job. Can’t quite get my head around what you are wanting to do but OB1 is a go-to adhesive

[Radian]

8 minutes ago, markc said:

OB1

 

Anyone getting a better price than £14.99 for 290ml from anywhere? I know it's supposed to be good, but...

[catrionag]

9 minutes ago, markc said:

OB1 should do the job. Can’t quite get my head around what you are wanting to do but OB1 is a go-to adhesive

Thanks Mark - sorry my description wasn't clear but thank you for the product recommendation!

 

Attached a picture of the detail just to clarify for others. Door (green arrow) and blockwork (blue arrow) is already installed. 75mm gap exists. 75mm sill (circled in red) needs to be installed with glue.

 

 

[Iceverge]

Can you just shutter them up and pour a sill in situ

[Temp]

OB1 lot cheaper on Amazon or at Wickes but check size is same. Under £8.

[Temp]

Consider masking everything with tape before gluing as adhesive is likely to escape?

 

[catrionag]

4 hours ago, Iceverge said:

Can you just shutter them up and pour a sill in situ

 

That's something I hadn't considered! We already have the sills so I think I'll try gluing in the first instance but if we do manage to bugger it up then this is an excellent backup solution. Thank you!