Drywalling and injection

[legepe]

Hi everyone, I have a commercial property that has signs of rising damp (see attached pics)
I would basically like to know if I was to drywall all the walls (like it has been done on the back wall) will this be a good solution, and by doing this, will it then not need to be injected?
The internal floor level is at two coarse of bricks above the pavement so it really doesnt allow much room to inject anyways? and could still suffer with splash back, no? also, I do not see any signs of the origional DPC, which I would expect to be slate?
Any advice here very much welcome?
Thanks
legepe

 

[Ivor Windybottom]

I'd start by looking at the drains. There's a lot of water going somewhere.

Get a spirit level on that concrete, see if it's taking water away or tipping it into the wall.

Have a walk around the next time it's raining heavily.

Get a camera drains survey.

It's vastly preferable to get to the root cause rather than covering up. You'd probably create a very damp, mouldy cavity by dry-lining it. It might look and smell OK for a few years, beyond that it will just decay.

 

[JohnD]

In your fourth picture the white efflorescence looks like it is centred on a black line that might be the dpc. So the water might be coming from the concrete floor inside the building. Which would most likely be a plumbing or drain leak. The building looks wetter inside than out. The wet appears to be next to a downpipe that may be blocked or leaking, or has a spill above. Have a look during and after rain.

Is the efflorescence lime? Scrape some off and drip vinegar on it to see if it fizzes. Are you in a hard water area, or is it dissolving out of the mortar? How old is the building?

Do not waste your time on chemical injection or drylining. Neither of these bodges will repair a leak.

Keep looking for the DPC. It is most likely two bricks above where ground level used to be when the building was erected. It might be visible under or beside a doorstep, or on another side of the building. It is common to find that ignorant buffoons have raised the level over the DPC by laying concrete or paving above the original ground level. This will also result in drain gullies looking sunken.

 

[legepe]

Thanks for your replies on this guys.. This job is a bit more complicated for me as a DIYer and I simply do not have the time to deal with it. so Ive got a builder, and a DP specialist comming beginning of next week to advise

 

[JohnD]

a DP specialist

Don't allow anyone who sells silicone injections near your property.

He will tell you to buy silicone injections.

 

[Ivor Windybottom]

Agreed, if you ask them if you need to pay them £1000s then they'll say yes. It's famous for being a cowboy industry.

Injections do have a purpose, after you've sorted out the actual cause.

 

[legepe]

I think the actual cause of a lot (not all) of this is simply for at least the last 8 years the room has been used as storage with things pushed up against the walls, and no air flow and never any form of heating
You will see on the pic (attached) that there is concrete either side of a wooden floating floor (to support the safes) in the middle, Ive opened up a small section and intend to open it up a bit more to make repairs to the wood that is rotting near the wall, this seems to be mainly caused by a bridge to the wood from the sub-grade, below where the concrete has been layered (no idea why they simply have not just concreted it all??)
I will look to see if I can locate the origional dpm, and I will put in at least one vent, which if I expose the fire place at the other end, it should create the needed airflow
I intent to use dryzone sticks on all walls (internally if possible) and then take off all plaster upto 1.2m and have it plastered with dryzone damp resistant plaster
I was given a quote yesterday of £4,500 to inject with dryzone cream and then take off all plaster upto 1.2m and put a standard plasterboard into the space with some type of membrain glued to the back to the plasterboard that is similar to the type you find in roofing, fixing the plasterboards with expanding foam (12.5m in total wall length around the room)(and was giving a 30 year guarantee!) Cant say they convinced me!
Anyways, what do you guys think of my plan to do what I see as a suitable solution to the problem?

 

[JohnD]

There is a lot of water in that room. It has come from somewhere. Lack of ventilation does not create water.

Forget about chemicals until you have found the source.

Once you have found the source, fix it, and forget about chemicals.

Draw a floor plan and mark where the damp is worst.

Add to the plan the positions of your downpipes, drains and waterpipes

Show us the plan.

 

[Ivor Windybottom]

Seconded. You're pratting about with magic potions when it's obvious there's a massive elephant in that room, just off-camera.

I've just moved a load of boxes that were against my external wall, been there for years. I've got a couple of black scuffs on the skirting that will probably rub off, I don't have a crumbling mushroom farm.

Dryzone is for walls that are a bit damp, not where the place is dissolving.

 

[Ivor Windybottom]

It looks to me like the plaster to the right of Henry is several shades darker, as it's so wet.

 

[JohnD]

When a floor goes rotten due to water, it is common for bodgers to pour concrete onto the wet patch to hide it. This makes extra work for the person who has to find and repair the source.

 

[^woody^]

Drylining is not a solution for damp, it's a mask. Deal will the cause.

The external pointing has failed for a start, so you need to determine if you have rising or penetrating damp.

 

[legepe]

Hi guys and sorry for leaving this post for a while, but ive been a bit busy with this and other things

My guess here is the problem seems to be mainly the following things - 1. no air flow under wooden floor (all moisture going from ground into room) 2. no air flow or heating for many years in room. 3. seems like the plaster was the wrong type that has been put on the walls in the beginning and was soaking up all the moisture 4. repointing required on external brickworks

I am pleasantly surprised at the condition of things considering the above, all the skirting boards were dry and do not show any signs of rot, which have been on the walls for the last 20 + years (apart from one small area around 12" long where the hole is in the passageway wall that looks like an air brick, but it is not, and I am not convinced the walls need injecting? and with some airflow and heating it will dry out naturally

The wooden floor does not seem to be overly rotten and maybe a couple of joists have to be replaced

The plaster that remains on the walls is very solid, and I guess seems to be some type of renovating plaster

Ive attached damp readings I took on first day and again readings on last day after I took off all crumbling plaster
I will put an air brick into passageway wall and somehow create air flow to the fire place-chimney stack through or around the sleeper wall

I would ideally like to just batten the walls and plasterboard them

Is there something I might be missing here, and is there remedial works before considering to batten and plasterboard, or is there something else you feel should be done?

Thanks again for your advice

legepe

 

[JohnD]

It's very noticeable that there is green moss at the base of the wall around the downpipe and soil pipe.

The concrete yard close to them looks like it has been patched and repaired.

When a drain in the ground is broken and leaking, it washes away the soil beneath, causing paving to crack and sink, and you often find the paving has been repeatedly repaired, instead of mending the broken drain,

 

[Ivor Windybottom]

The next time it's raining, stick your coat on, grab a brolly and go and have a look. You may learn lots.