DIWHY Wet Rot, Suspended floor and masonry walls

[Craabonn]

Hi all,

Made a big leap into renovation our dining room trampoline floor in my 1920s house. I mean suspended floor where the joists have bounce. However the more I see the more I wish I did not see.

Sleeper walls
- timber plate - I have began to cut these back ready to be replaced.
- Re-mortar and new DPC
- I have taken the sleeper wall down as they meet the patio wall, as the mortar as failed, will re-lay these too.
- what is suitable as the timber plate, i;ve been struggling to figure this out. Are the following options suitable? The original plates 18 mm thick, and these are thicker, so i'll make the difference up with mortar thickness? (1. https://www.wern-wood.com/products/...1&_sid=0314587bf&_ss=r&variant=55038974656836 or 2. https://www.wern-wood.com/products/...8980&pr_ref_pid=15018045899076&pr_seq=uniform)

Patio door cavity & reveals (images 4)
- bricks and mortar at open lip of the cavity wall is weak, with a few bricks removable by hand
- plan to even out the cavity opening to insulate cap along the edge and not to block the entire cavity.
- the cavity space from left to right is completely full with build-up. I have taking the interior patio door wall down to the ground to clear out. The reveals are very clogged, and only able to get so far.
- Will re-lay these.

(images 6, second post) Joist ends and party wall
- 2 of 3 ends have fully rotted and failed
- Where I have truly hit the wall on this job, is the mortar failing on the party wall and really could do with pointing in the right direction.
- images 6a & 6a1, if you look closely, the mortaring of the bricks at joist level above the DPC have worn away and are essentially floating.
- I hope to build a new sleeper wall for the remedial of joist support, set in from the party wall in the alcove (see image 2), OR should i replaced the joists entirely and set them back into the original slots? (see second post, image 8 )

The dimensions of C24 wood (47 x 100m is confusing me, as this differs to the original, older timber joist of 50 x 100.
- Could I go 47 x 125 and cut it down?

When re-mortaring, I plan to use lime or plasticiser additive where it has originally failed.

The crawl space was filled to the brim when I opened it, just over a tonne has been moved, one vent was blocked by build-up and another was blocked intentional as part of historical work on the house prior to my existence.

Moisture is from poor ventilation and ground saturation from the outside, where water is draining poorly away from the exterior wall (will upload a picture tomorrow). I do plan to address the external drainage.

I typed out more then lost my draft, its 11pm and I have a 2 year old. More to come tomorrow!

 

[Craabonn]

further pictures.

Overall level along the length and width of the room seems fine.

 

[Craabonn]

further pictures