bonding larger areas

[1stProject]

hi there,

many thanks for all your responses on the bonding cracking thread.

I wonder if i may ask for some more advice

I have hacked out large areas of plaster where the plaster had blown, these areas now have exposed brickwork, (the bigest area being the entire hallway, other areas are for e.g, above door frames upto ceiling) can i apply bonding strraight onto this surface or do i need to prepare it with metal mesh, also would i do the same with the timber above and around the internal door.

another question,
my door frames are not exactly level with the old plaster, something i noticed when i took the architraves off the door frames, a new coat of skim/plaster will bring it up even more so there is no way they will level up with the door lining, how do i go about rectifiying this situation, some ideas i have already are to put a thin strip of wood arounnd the door frames or to change the door lining alltogether, the linings i have been looking at either hardwood or oak vaneer come up the same with as the existing linings i.e. 131mm.

Any help much appriciated.

Many thanks

 

[1john]

pva twice before bonding, making sure that the second pva coat is tacky when you apply the bonding.

cover the timber with overlapping plasterboard if you can afford the depth, or with slate if you cant

Either replace the linings (they will prob be shapless anyway) or as you have already said, attatch a rip onto the existing linings to bring them out

 

[NickB_99]

I have hacked out large areas of plaster where the plaster had blown, these areas now have exposed brickwork, (the bigest area being the entire hallway, other areas are for e.g, above door frames upto ceiling) can i apply bonding strraight onto this surface or do i need to prepare it with metal mesh, also would i do the same with the timber above and around the internal door.

Bonding is intended for low suction backgrounds. Different types of brick have differing levels of suction, but would recommend any use of Bonding has PVA/water applied as 1John suggests or you will prob get problems as you found with your chases. There are other plasters (Hardwall, Browning) or indeed Render which may be more suitable.

The mesh is only needed really where extra strength is needed in the plaster e.g. where the brickwork below has cracking in the mortar and some movement has been evident.

If you are looking at the whole of the hall, then it is perhaps more than a patch up job (where you can level off using the surrounding plaster) and you would either need to float & set or use plasterboard. I would suggest if you are new to it, float & set is more difficult than using p/board, and it may be worth considering getting a pro in for these large areas.

Not entirely sure what you have in mind with the timber above/around the door - did you mean attach mesh to it? If so, this isn't necessary. You can plaster up to wood - plaster does not stick that readily to it.

another question,
my door frames are not exactly level with the old plaster, something i noticed when i took the architraves off the door frames, a new coat of skim/plaster will bring it up even more so there is no way they will level up with the door lining, how do i go about rectifiying this situation, some ideas i have already are to put a thin strip of wood arounnd the door frames or to change the door lining alltogether, the linings i have been looking at either hardwood or oak vaneer come up the same with as the existing linings i.e. 131mm.

Not had much experience with doors, but if you've taken the architraves off, your veneer may work ok.
A skim finish is usually of the order of 2mm, so not thick.
I think with my doors where I've float&set adjacent, I've left the architraves on and used the architrave as an edge to finish up to.
In fact if the finish is feathered thin to the edge of the frame, it may only need a line of caulk to fill in the remaining thin gap. Though this may not be the most elegant solution!

 

[Micilin]

Im guessing that the timber around the door is just making the brickwork opening the right size for the doorframe (it may have been a sub frame or profile but that hardy matters now)

To plaster over this -

Make sure you have 10-12 mm clearance to take the plaster and eml. If not, we'll deal with that later.

Staple some dpc, building paper or just polythene to the timber, covering it

Get some eml which is wide enough to cover the timber and at least 100mm past where it meets the brickwork.

If it is a roll of eml, stretch it to make it flatter and easier to fix.

If it is not nice and flat Bend it along its length, just slightly so that it is slightly concave

With the concave side facing the wall fix it to cover the timber. BUT only put the fixiings in the brickwork, not the timber*. This will allow the timber to move independently behind the plaster , so that when the door slams etc the plaster will not be prone to cracking. The concave shape of the eml will spread and force itself flatter so that it does not protude proud of the intended depth of plaster.

*For wider timbers eg ply etc you will need fixings in the timber, but then in that case we are talking about the timber being an integral part of a wall

Now if the door frame /liner is not wide enough two easy options -

1 - plant a 8, 10mm as suitable strip(door stop may do) onto the frame. This wants to be on the non -hanging side so if the problem is on the hanging side, you may have to move the frame over and put the extra on the other side.

2 - Rebate the archtrave by the amount that the plaster is proud