Strange Damp Problem

[mykp]

I am in the midsts of purchasing a new house and we have just had the survey back and they have listed Penerating Damp in one of the down stairs rooms. Now as the house is a pretty weird construction I have put together a little diagram which shows the house layout more than any words I could type ever could.

Now I was wondering if anyone had any information or comments on this type of house and how to fix the damp. It is extremely mild damp and is limited to a block about 8 inches in diameter.

I have a specialist coming to look at it tommorow but want additional information so I can step back to the seller to try to get some more money off the price of the house or an idea of the costings involved of other types of treatment.

Is this likely to be a big job or is there some specialist treatment for walls of this nature.

cheers
mike

 

[masona]

Have a read at this.

 

[mykp]

Masona,

I'd already read the post you pointed to but have read it again incase I missed anything.

The damp I mentioned is not of the rising variety but is about 5 foot off the ground. After quite a lengthy discussion over the past hour, me thinks that the wall behind where the damp is, is not all the way to the top of the room but is back filled up to about where the damp patch resides.

Now we've come up with a few extra ideas about what it could be.

1. The bathroom is behind the wall marked on the above diagram but is above the level of the room. There could be a leak in the bathroom.

2. The house has been empty for 4 months over winter and it might be condensation.

3. One of the outside walls has a breach in it.

4. If the level behind is backfilled it wont have any type of drainage in it!

Other than that i'm sure the DPC will inform us tommorow!?

The house is about 40 years old.

mike

 

[masona]

cavity or solid wall ?

 

[mykp]

Cavity wall

 

[masona]

Awkward without seeing it,if you have wooden flooring lift them up and see if you can smell any damp.If the outside wall is okay then my guess would be one of those two,

1. The bathroom is behind the wall marked on the above diagram but is above the level of the room. There could be a leak in the bathroom.

2. The house has been empty for 4 months over winter and it might be condensation.

or the tie-in wall bracket not fitted correctly between the 2 internal wall for outside rain to transfer thru' the bracket but this only happens after very heavy rain on your wall so this would be unlightly.

or do you know where your water mains come in from?

The problem might go once you got the heating on plus ventilation.

 

[mykp]

Cheers for that Masona,

I've borrowed a damp meter and its the type which beeps louder the wetter the wall. Not the type that just beeps. so I should be able to pinpoint it to a greater degree.

I'd never though of the bridged problem. It did absolutely bucket down on Tuesday night and the survey was done on Wednesday morning.

hmmm!

mike

 

[oilman]

If it's a damp meter which measures electrical resistance, don't believe anything it tells you. I have two, and when they are used to measure damp in walls they LIE!!! This is because the conductivity varies with the salts in the masonery as well as the moisture.

 

[mykp]

I've been to the property today and had the damp proofer round to look at the problem.

This guy was recommended by two seperate friends who dont know each other so he must be okay, plus his company specialise in cellars and below ground damp problems.

Heres what he had to say.

The bit on the diagram is actually brick with a cavity wall. The floor above is a concrete floor. This is know from other houses in the area of the exact same contruction.

The remedy he suggested is as follows.

The plaster is to be hacked off up to 12 inches above the concrete floor on the affected side of the wall, this is about 4 feet high and about 1 metre round the adjoining wall. They will then inject both sides of the cavity wall from the same side and left to dry for 24 hours. The wall will then be tanked, and left to dry for 48 hours before a second layer of tanking is applied. this is again left to dry before being plastered.

The other solution on offer was to hack up all the concrete floor, but this would involve removing the bathroom and staircase, then digging up the back fill, then putting in a barrier damp course.

The first method comes with a 25 year guarantee and the second comes with a 20 year guarantee.

I should know more tommorow when he emails me over the full quote with pricing.

mike

 

[Big_Spark]

Thats all well and good, but if you don't know what is causing the damp, this could just be a temporary measure.

If it is a leaking pipe it would make sense to find it and fix it, the wall would then dry out and the cost of the DPC would be saved.

Tanking a Damp wall is not solving the problem if you cannot locate the source of the damp.

 

[masona]

I'm 100% with FWL_Engineer on this one,

I have no time for these dpc company unless the dpc is broken which is very very rare these days.If it's broken dpc then repairs it,not chemical treatment.

 

[mykp]

The dilema is this.

Do we got for the short term fix. IE the damp repair.

or

Do we goto massive expense of ripping out the bathroom. ripping up the concrete floor and digging out all the back fill to find out what it is.

I fully understand what you guys are saying and i'm prepared to do the above. However the sellars are prepared to pay for the DPC.

I am of the opinion that the problem isnt damp but something leaking in the bathroom as the damp is not located at the bottom of the wall but about 24 inches off the floor in the corner of the wall. Its almost like something has been leaking and collecting in this area!

To be honest I'd be loath to let somebody hack the house to bits and wait and lift the concrete floor, however!

mike

 

[masona]

The dilema is this.

Do we got for the short term fix.

Never !

To be honest I'd be loath to let somebody hack the house to bits and wait and lift the concrete floor, however!

Agreed, best thing to do is to hack off where the damp area is and hack off the plaster including brickwork and investigate from there,a lot cheaper this way.