What is causing the damp in these photos?

[tim00]

1. Do as your list proposes.

2. Do not go near any waterproofing agent, it will only cause further difficulties down the line.

3. Ignore the technicalities of DPC injection. Render the interior walls, including the fireback and cheeks with a 4-1-1 mix to 1M height.

4. Your floor will need excavating and renewing - research on here, installing a solid floor. Remember that your FFL must match the adjoining FFL(s). Any perished brickwork revealed, should be replaced, one or two at a time.

note: your gable brickwork is a lovely soft brick that will look terrific on summer evenings, it will glow, and be well worth all the trouble.

 

[mcjizja3]

Thanks once again, unfortunately you leave me with more questions, sorry!.

Ideally I'd like to leave the cheeks (even if just the front face) and the arched lintel bricks exposed. I have managed to salvage a few of the original bricks when clearing out the fireplace that are in great condition and was planning on replacing the odd ugly one and give any others a good clean.

Can I render as you suggest, but selectively? Is there a breathable masonry sealant I can/should use on the brick that is left?

When you say the FFL must match the adjoining FFL, do you mean for regulatory, aesthetic, DPC or other reason? The reason I ask is there are 2 adjoining rooms, both at different levels.

 

[tim00]

1. Of course, you can render selectively. No problem.

2. No. No "masonry sealers". Leave the open brickwork alone.

3. Does one of the adjoining rooms have a step-up, or a step-down? If yes, then ignore that room's FFL. Now match the FFL of the new work to the remaining rooms' FFL.
The idea is to have a uniform FFL where possible. Steps are not dangerous per se, but even tiny differences in FFL heights can create toe-trippers.
Also, level floors enable floor covering's to flow from one room to the other.

 

[mcjizja3]

Great, Now that I have some direction I'll get started.

One question about the mortar. The current stuff is very textured:

Untitled

• mcjizja3
• 4 May 2012
• 1

I realise some experimentation is in order to get the best match, but do you have any idea what would have been used to achieve this? Some kind of fine Ballast or Shingle?

 

[joe-90]

It's pretty hard to get a really good copy but your best bet is Sharp sand plus red builders sand and a weak mix.