Update; what do you think?

[Dazed&Confused]

Hello you wise, knowledgeable and kind people!

I posted ages ago because I was overwhelmed with my Victorian cottage, and I wanted to share an update and my ideas for solving my damp problem to see what you guys all think.

We thought the house was built in 1885, but my brother-in-law found a map from 1842 that has part of the house on. So we now know that the house has had three extensions in total over the years.

So, we dug some investigatory holes around the house:

This is the newest part of the house (apart from a first floor extension), with concrete footings:


This is the original house, which is just bricks straight onto the clay earth:

(Don't ask about the wires - someone incompetent has been messing around at some point!)

This is the first extension, which turned a coal shed into a single-story habitable room:

We think the coal shed was converted by the 1880s, but the doors and windows seem to have been moved throughout the 1900s.

There are airbricks around the property, but no evidence of them inside. Measuring and comparing inside and outside shows that they are actually below the level of the current floor! No wonder it's all so damp!

We scraped some mortar out and it seems to be lime inside with modern pointing, but it's all soft.


We discovered one source of the damp - my neighbours' downspout, which has a hose pointing straight into one of our airbricks!


We then (gently) broke through the concrete in a room in the original part of the house. It's only 1" thick(!) with just sand/soil underneath, right down to the original tiles, which are laid straight onto the clay earth.


There is a boarded up... something in one of the rooms in the original part of the house, and we finally cut into it and it is an original beam, which is fantastic, but I'm still curious as to why it's been boarded up.


So, given all that we've found, the plan is to dig a trench around the outside down to below the rudimentary DPC on the original house and brace it with old slate tiles from the roof.

Then we're going to take the flooring out in the original part of the house, down to the original tiles, and put in suspended timber. We will put membrane on the base of the joists, etc, to prevent moisture migrating through the wood, and add air bricks so there's one between each joist.

Once we've done that, we can start to think about the newer parts of the house!

Any thoughts?

 

[Feltwell]

That downpipe, with the hose pointing directly to your airbrick - that looks suspiciously like a rainwater diverter to me, meant for diverting downpipe flow into a water butt!

If I'm right and it's not been blocked off, every time it rains everything that comes down that downpipe flows neatly through your airbrick..... One to check out urgently I'd suggest!

 

[Dazed&Confused]

That downpipe, with the hose pointing directly to your airbrick - that looks suspiciously like a rainwater diverter to me, meant for diverting downpipe flow into a water butt!

If I'm right and it's not been blocked off, every time it rains everything that comes down that downpipe flows neatly through your airbrick..... One to check out urgently I'd suggest!

Thanks Feltwell. I agree - I will be speaking to the landlord as a matter of urgency!

 

[Feltwell]

Quick fix is just plug the hose - they're designed so that when the water butt is full, water backs up the hose and then the downpipe operates as normal, so you won't cause any problem for the neighbour.

 

[Dazed&Confused]

Quick fix is just plug the hose - they're designed so that when the water butt is full, water backs up the hose and then the downpipe operates as normal, so you won't cause any problem for the neighbour.

Thank you! I've been wondering how to stop it for now without causing different problems! It's hard to inspect it because it's right by the neighbours' window, and we do not get along! I shall plug it up this morning.

 

[Feltwell]

Well, you won't cause any problem for the neighbour so long as their drain is working!

 

[Feltwell]

Had a look at your post properly now - you've got quite a lot in there.

One thing at a time. First off with damp walls, always look up - is the guttering in good condition, does it catch all the rainwater? Are hoppers or downpipes blocked? Do downpipes actually flow into drains? Lift some manholes up, stick a hosepipe down the downpipes, satisfy yourself that it's flowing away OK.

Next thing, ground levels - should be lower outside than inside, should be lower than the damp proof course, which your house has *probably* got - but maybe not all the way round if you've got things like converted coal sheds. It's usually a layer of slate or bitumen, often it'll be at the top of the airbricks. Your plan to lower ground levels and hold it away for the walls sounds sensible.

Which brings us neatly onto airbricks, you shouldn't be able to see them inside, as they should be there to ventilate the gap underneath suspended wooden floors. However - if they've been blocked in the past, if walls have been damp and joists have rotted, builders have a very nasty habit of ripping it all out and putting a concrete floor in, usually badly. Even if a DPM was put under the concrete, this can push damp into the walls. Only real cure is break the concrete floor out and reinstate a suspended floor. However, it is a case of it *can* cause problems, it doesn't in every case.

We then (gently) broke through the concrete in a room in the original part of the house. It's only 1" thick(!) with just sand/soil underneath, right down to the original tiles, which are laid straight onto the clay earth.

Yep, that would be a prime cause for damp! If you want to keep the same floor level as now then a suspended, insulated floor with an airbrick vented void underneath would be how I would do it.

There is a boarded up... something in one of the rooms in the original part of the house, and we finally cut into it and it is an original beam, which is fantastic, but I'm still curious as to why it's been boarded up.

Could be aesthetics, could be at the insistence of Building Control - if creating an opening in a wall and putting a timber beam in they usually want 2 layers of plasterboard (or 1 of fire retardant plasterboard). If it's an old adaptation, even if an existing beam, they may have required this, as a fire precaution.

Then we're going to take the flooring out in the original part of the house, down to the original tiles, and put in suspended timber. We will put membrane on the base of the joists, etc, to prevent moisture migrating through the wood, and add air bricks so there's one between each joist.

Membrane won't do any harm, but if above DPC it shouldn't be necessary. I'd do it though, I'd also be tempted to use treated timber and paint some epoxy primer onto the end grain if I was doing a new installation within walls that may not be fully dry for a while. Belt & braces!

You don't need that many airbricks. A cross-flow is what you want - ideally opposing walls with airbricks on both sides if possible. 2 on each wall is fine unless the room is huge, Don't forget you can vent into other rooms with suspended floors or into a cellar if need be. You want a bit of a breeze under there, avoiding any pockets of stagnant damp air, so make sure there is at least a few inches of clearance under the joists and no rubbish to block anything down there.