Damaged party wall under floorboards

[monosyllabikgurl]

Hoping for some advice here:

We live an a period terrace house (late Victorian/early Edwardian), and have problems with smelling cigarette smoke coming from our neighbour's house. We have exposed original (and obviously gappy) floorboards in the front room and when they smoke in the house the smell is very strong. We have a toddler and the second hand smoke concerns me. Last night we pulled up a couple boards to investigate. We were expecting to find some loose mortar surrounding the joists going into the party wall, which we planned to fix by replacing the mortar. However, after going into the crawl space we found HUGE gaps in the brickwork of the party wall (pictures attached). You can see right through to next door, and some gaps look big enough for a small child to crawl through. Our front room is actually knocked through into the adjoining dining room, and there is brick wall under the floor separating the two that is perpendicular to the party wall (with a gaps you can see through). Its not possible to crawl through to the other side, so we would need to raise floor boards on the other side of the room to have a good look at the party wall on that side of the room. The final picture shows the party wall on that side of the room looking through this gap. I hope that makes sense.

My questions are:

1. We assume this is a job for professionals, and we are worried that there are structural implications. Are we going to have to lift more/all the floorboards (an risk damaging/losing the original boards in the process) for a buider to have access to fix the brickwork? Will this require party wall act? Is this likely to be very costly? We have been saving to have the kitchen and bathroom done this summer and are now worried that the cost of this will impact the project.

2. Once in the crawl space, we noticed what looks like white mould on the soil underneath. You should be able to see in the second to last picture. Is this something to worry about or to be expected? Google suggests all white mould is a health hazard... There is definitely airflow - we have two air bricks at the front and two at the back that all look clear and the joists look OK.

Any help/advice would be appreciated!

Thanks so much.

 

[Bonni]

It appears to be a dwarf wall, built quarter bond to allow air flow under the joists. I'm puzzled why that would be on a party wall so I can only assume the house was one and then split into two at a later stage. Some areas were omitted/cut out to allow crawl space.

Without surveying it, if you wanted to block the gaps up, you would need sufficient air bricks around both properties to vent their floor space, otherwise joists could rot.

 

[monosyllabikgurl]

My mistake - there are 4 air bricks at the front and two at the back. I missed the two that were on either side of the bay.

Thanks for your reply. I suppose it is a possibility that it was was once one house? The neighbour in question is the mirror of our house, but the row of terraces are all the same construction with doors on either side. There was never a door in the centre between the two bay windows as you would expect if it was originally one house.

 

[cdbe]

That doesn't seem right. There are cables running from one house to another and the party wall above ground must be built off the floorboards. Are you sure you're as far under the house as you think? My house has two of those sleeper walls before I get to the party wall.

 

[Alastairreid]

Thats a sleeper wall.

 

[stuart45]

What's your party wall above sitting on?

 

[monosyllabikgurl]

Thanks everyone for the responses. Having now looked up sleeper walls (apologies but total novices here) that does seem like what they are. Is it normal for terrace houses to have sleeper walls as party walls?

cdbe - I see your point. There is something behind this wall (I.e. it is more than one brick thick) but the gaps/holes that are there go straight through into next door. We think the electrical cables are ours and not next doors - this region is directly under our mains fuse box.

If this is how the walls are meant to be, with all the gaps for ventilation, then obviously we do not want to seal them up. But does this mean we are out of options for fixing the smoke issue? Is it possible there are gaps somewhere that are not meant to be there that could be filled?

 

[stuart45]

Sleeper walls are normally honeycombed but the top course is usually solid with a DPC on top and then a wall plate to take the floor joists.
Party walls of that time were normally solid 9 inches thick, although some only 4. They shouldn't be honeycombed.