Replacing a rotten joist supported in a stone wall.

[mike1978]

OP,
1. If you use bolt-on's then keep to the same section: 6" x 2" (no 4" x 2") - the thing is you've not indicated any damage on the far wall of the kitchen - have you lifted any boards against that wall or seen damaged joist tails?
2. Is the water mains in a modern plastic pipe - it should not have a sharp ninety degree bend.
3. There are two steps down to the kitchen - is the house on a hill?
4. Typically, remove all units and apps from the floor to give work room - messing about with sink positions will waste time.
5. Is the wall 800mm solid?
6. Your rear elevation will need a few air bricks.
7. Photo #5 shows what appears to be dry rot tendrils - is that a vegetation?
8. All plaster/render should be removed back to stone - note the render is running down below the FFL to the sub soil: knock it all off.

FWIW:
What do the holes in the wall in the last pic mean?
The horizontal soil pipe needs clipping - does the vertical stack also require clips?
At present, how are the sink and any apps in the kitchen drained?

Hi,

1-Yes, will be keeping to 6 x 2 - i`ll be lifting a few boards on the other wall either tomorrow or monday i think to take a look. I did replace a radiator on this wall so have previously a few of the joists which looked fine, but will make sure.
2- the white plastic pipe you can see is the drain for the sink - the copper one behind in green foam is the feed to a outside tap ( at a guess!). Although the main feed from the water main tees into this pipe to connect to the sink and the rest of the house. Should this not be tee? All of this pipework will be renewed soon, so would be good to know if it shouldnt be a 90 degree connection?
3 - 2 Steps - yes, the house was originally a store house for the mill and various sections been grafted on to it over the last 150 years or so. I think the rear probably does slope down on a slight hill. Haven`t had the floor up in the lounge though so can`t be sure of that.
4 - yes, all the units, worktop etc, is going to be pulled out to enable the work - there`s nothing like having to struggle round existing units,etc !
5 - that interior wall is the original rear wall and 60cm thick of solid rough stone. Back wall of house is 40cm solid rough stone.
6 - agreed - a couple of air bricks will not go a miss and are in the plan.
7 - There is no vegation that i can - just dust, rubble, dampness and a few slugs There is some green paint hidden under some of the render which may be poking through though.
8- again, agreed - all that render has to come right off .

The holes in the last pic are from a small banister that was there and was pulled off within a week of moving in by my 3 year old son! Gives you an idea of the quality/choice of the plaster/render.

Soil stack does need clipping. Drains you can see in pic - disappear under the floor and into a drain outside i think. Will be lifting more boards to investigate this.

The house has been attacked by many botches over the year who may have best intentions, but probably did more harm than good. The best one recently has been the bath has never drained quickly (like 15minutes) and would gurgle up into the sink and bidet -)). Finally got round to having a look. The pipe joining into the outer soil pipe was blocked, but then i realised with the floor up, that the installer had drilled the hole in the outer wall to high and instead of redrilling the hole at the right level, had simply bent the drain pipe up to meet it a couple of inches higher than it should have been. Effectively, there was a 2m trap running right across the bathroom. I`m not a qualified plumber, but by all accounts, i know that gravity goes down!!

 

[vinn]

1. Then only one side of the room has damaged joist tails so far. Later, If you want, I'll take you through how to bolt-on and do pockets in the wall.
2. Immediately your water mains enters the house it should be given an accessible stop-tap isolator.
Ref 90 degree conn's - they are not wrong as such but its best to use slow bends for water.
3. Is the kitchen floor level with or below the external ground level?

In the proposed new plumbing set-up there should be a yard gulley discharging into the soil pipe drainage below the yard surface. The sink and apps & any down pipes can then discharge into the gulley.

The yard wall abutting the house might be causing penetrating damp at higher levels?

 

[mike1978]

Hi,

That`d be great to get some advice on the bolt ons and pockets. I got round to lifting the boards on the other side today - it looks like the joists here are dry. It actually looks like there is a layer of red brick at the bottom which has been the foundation for the stone wall.

I think the previous owner said to us they replaced the floor and electrics when they moved in in the early 90s. They`ve obviously been renewed at some point, so i guess they`ve been in for 20-25 years. You can see in the pics, they`ve been cemented in but are dry. Wall is a little damp at the bottom with about 3 layers of different renders - i`ll probably knock this off.

Floor is the same level as outside by the way.

Here`s a few pics anyway

Thanks, Mike

 

[vinn]

Keep going - open up all along the wall.

You should knock off some of the mortar, and probe around the joist tails in the wall pockets, feel under the joists - thats bad practice to build-in the tails with no ventilation or DPC wrappings to cap them.
You should also dig out below the joists to give a good earth clearance void.

Elec cables should only be run in safe zones but its not retrospectively required - its also best practice is to use metal channels.

When both sides of the kit are opened up then we can go a bit further.

 

[mike1978]

Thanks for the help - appreciate it

It'll be a couple of weeks before I start the work properly, but will reply back when I start.

Cheers , mike