removing debris from cavity wall

[maggie73]

have posted in past due to damp problems: 1860's stone built end terrace built into hillside up to top of livingroom ceiling at back of house. Public steps come down gable end of house and there is a road immediately adjacent to house at back. Property renovated in 60's by council which was probably when cavity walls added along back and gable walls on ground floor and there is some sort of dpm between in the cavity wall below floor level, so in theory no damp should be present. Scottish lime centre came down for a look and confirmed cavity walls etc all built correctly but didn't look in cavity walls. Removed a brick at weekend (plaster not very hard to get off!) and a fair build up of sand inside cavity, probably up to level of top of skirting board along wall, and silted up beside chimney breast and at corner of gable/back wall, where plaster most damaged. The outside wall feels damp to touch but fully expect that as built into ground. The sand itself feels a bit damp, bricks feel ok, but it's been dry for a good 2 or 3 weeks here. So, I am quite pleased about this as it was the result I was hoping for as debris can be removed and bricks/replastering assessed. My question is should we add some airbricks at skirting level when we have let it dry out etc. There is one vent in that area at the top of livingroom wall that vents through to the outside at the moment. I feel it could benefit from added ventilation but worried it may increase condensation in the cavity in colder months.

 

[MdB]

Vents from the outside into the cavity are a good idea if you want the cavity dry (not so good for best heat retention though). You definitely don't want vents from inside into the cavity. Warm moist air will travel from your house into the cavity and then cool and condense. It will also cause a lot of heat loss if there is a vent outside as well.

 

[maggie73]

Thanks for the reply and that makes sense. The vent at the top of the livingroom wall vents into cavity and there is a vent to outside at the top of the steps on the outside wall, but that's the only inside wall vent. I suppose that vent is a requirement for the old gas fire or something, I'm not sure. Removed a section of plaster today and so far brick in good nick

 

[stuart45]

Cavity walls used to be vented, but it was found to cause cold spots on the inside walls and isn't done now.

 

[maggie73]

Back at this old problem again, after putting it off for a while. Plaster removed to about 1m high, a couple of bricks removed at floor level, and removed a fair bit of sand/debris. However, the cavity itself is only about the width of a brick and it's difficult to get an arm plus tool in to get down to the bottom of the cavity. Probably take another brick out beside the space we are working at just now to see if that makes access easier. I just wondered if there is any magic industrial hoover type tool that can do this job for us?? I'm reluctant to get a builder to do it (we will need a builder eventually for fireplace work) as it will probably be costly and at least if we remove the debris ourselves, we know we've removed it completely. Am I right in thinking it would be a lengthy and therefore costly job for a builder? And if there are no magic hoovers, are there any recommended tools? Currently using a plastic milk carton cut in half with the handle remaining....

 

[Zebra]

I think I found a Henry rather good at removing stuff from inside a cavity.

 

[maggie73]

We've already broken one hoover (think it was on the way out anyway), but it was no Henry. I'm not allowing our Henry to be used for this!! Though I may be persuaded if we can't get at the bottom stuff.

 

[88v8]

I suspect a hire shop would have an industrial vac that would do the job.
Agree about doing the work yourself, no point paying a builder.

Ivor

 

[billybuntus]

Hire an industrial hoover. Buy around 20 hepa filter bags to use with it. They are designed to hoover up debri around site so are ideally suited to your tak and come with extra long hoses.

I cleared 20 sacks of rubble from underneath our floor with one. Brilliant bit of kit and takes a fair amount of dust to clog it up. A henry would be painful in comparison.

 

[Zebra]

We've already broken one hoover (think it was on the way out anyway), but it was no Henry. I'm not allowing our Henry to be used for this!!

Oh go on. He likes it! Mine's still smiling, and he's sucked up all sorts of filth, all the mortar from the repointing, all the cement render, everything.

 

[maggie73]

oh, that sounds promising, will get looking. Thanks. No, I'm not going to kill Henry.

 

[FamilyWiggs]

I picked up a "broken" Henry on ebay recently for 25 quid plus local pick up. There were plenty of spares or repairs on there. A very common fault is the contacts in the cable winder break. A £3 contact kit, 20 mins for the older gene puddle of teaching him to repair things, and we have a working Henry. They cost more than £100 new.

Lots of bargains on there.

 

[maggie73]

Yip, actually started looking on ebay and stuff for Henrys.

 

[a twig]

Another vote for the Henry's, I inherited my Mum's after she "upgraded". It gets used for everything, sawdust, bits of broken plasterboard, small bits of rubble etc. Absolutely fine, and a doddle to repair as well (although touch wood mine hasn't needed it yet)!

Top tip - the hose design sometimes causes larger things to get stuck in it especially if it isn't straight when you are hoovering larger things - a broom handle is ideal for unblocking!