DPC installed two owners ago

Emily_Joy

The house was built some time between 1910 and 1920.

It appears "vertical DPC" (I am not sure what it is) was installed in 2007 and most of the walls have been replastered inside to 1 meter high by a local damp proving company. They provided 30 years guarantee for "rising damp" to the owners at the time. But the house was sold twice since then.

There is no paperwork whatsoever regarding the issues that the DPC meant to solve. There is also no paperwork regarding the materials used, just a plan of the building showing the parts where the walls were replastered and vertical DPC installed.

At the moment there is no sign of any damp issues and the house appears to be pristine.

Any thoughts?

stuart45

A DPC for rising damp is usually horizontal, a minimum of 150mm above ground level. A house of this age would normally have one anyway. New ones are often installed in walls where the cause of damp isn't rising damp and aren't needed.
A vertical DPC is usually to stop penetrating damp. An example is on cavity walls. At the door and window opening jambs, the brickwork on the inner skin was returned to meet the outer skin. This meant that damp could penetrate here as the cavity was closed, so a strip of 6 inch DPC was inserted between the 2, vertically.
A house of this age might not have had this vertical DPC when originally built.

stuhse

In my experience damp prof guarantees are not worth the paper they are written on.  The best evidence is the work was done in 2007 and  "At the moment there is no sign of any damp issues and the house appears to be pristine."   .  So it would appear to be working just fine ?

Emily_Joy

stuhse said:

In my experience damp prof guarantees are not worth the paper they are written on.  The best evidence is the work was done in 2007 and  "At the moment there is no sign of any damp issues and the house appears to be pristine."   .  So it would appear to be working just fine?

I am worried the DPC application together with replastering just masked the real issue for the time being that will need to be dealt with sooner than later. But it is possible of course I am overthinking it.

stuart45

The new plaster will often hold the moisture back from the surface, and it can get through when any movement in the wall causes cracks in the plaster.
However companies in more recent years have insisted on other works being carried out in conjunction with the wall treatment.
These can include the lowering of ground levels, cleaning out the cavity, repointing, etc. 
These extra works will often stop the cause of the problem, so there may not be any further issues.
As condensation is often the cause of the problem, someone who moves to a new house and heats and ventilates the rooms properly could be solving the issues anyway.

FreeBear

Emily_Joy said:

The house was built some time between 1910 and 1920.

It appears "vertical DPC" (I am not sure what it is) was installed in 2007 and most of the walls have been replastered inside to 1 meter high by a local damp proving company. They provided 30 years guarantee for "rising damp" to the owners at the time. But the house was sold twice since then.

There is no paperwork whatsoever regarding the issues that the DPC meant to solve. There is also no paperwork regarding the materials used, just a plan of the building showing the parts where the walls were replastered and vertical DPC installed.

At the moment there is no sign of any damp issues and the house appears to be pristine.

Any thoughts?

The "vertical DPC" is probably a waterproof membrane with a "special" render & plaster slapped over the top (or it could just be a layer of waterproof render/plaster). Normally done in conjunction with a chemical injected DPC - Is there a row of holes drilled in to the external walls just above ground level ?

Built between 1910 and 1920, it is probably a solid stone or brick wall - Slapping modern materials on is a bad idea, and these damp "cures" often end up doing more damage than they "fix". Unfortunately, it is no longer a pristine property (in my opinion).

Emily_Joy

No, there is no "row of holes" otherwise I would have noticed it sooner! The only evidence I have is this plan: (which I appreciate is not very easy to read). I think it meant to show there was indeed some "horizontal DPC", vertical DPC, and "replaster to one meter".

stuart45

It looks to me like it has vertical tanking, a vertical DPC in the corners of the lounge, and replastering.
Avoid drilling through any tanked areas.

stuhse

Emily_Joy said:

stuhse said:

In my experience damp prof guarantees are not worth the paper they are written on.  The best evidence is the work was done in 2007 and  "At the moment there is no sign of any damp issues and the house appears to be pristine."   .  So it would appear to be working just fine?

I am worried the DPC application together with replastering just masked the real issue for the time being that will need to be dealt with sooner than later. But it is possible of course I am overthinking it.

Its lasted 15 years---it would be coming through now if it was going to - its a successful job..time has proved that.  As others have said it sounds like a vertical membrane has been installed which is way superior to the chemical injection  that was typically done in the 90s. The vertical membrane is the ultimate way of dealing with it --its already been done.

FreeBear

stuhse said:

Emily_Joy said:

stuhse said:

In my experience damp prof guarantees are not worth the paper they are written on.  The best evidence is the work was done in 2007 and  "At the moment there is no sign of any damp issues and the house appears to be pristine."   .  So it would appear to be working just fine?

I am worried the DPC application together with replastering just masked the real issue for the time being that will need to be dealt with sooner than later. But it is possible of course I am overthinking it.

Its lasted 15 years---it would be coming through now if it was going to - its a successful job..time has proved that.  As others have said it sounds like a vertical membrane has been installed which is way superior to the chemical injection  that was typically done in the 90s. The vertical membrane is the ultimate way of dealing with it --its already been done.

No.

The correct way to deal with damp is to cure the source of the problem rather than slapping questionable "cures" on a wall to mask the issue. Old properties need to be treated with respect and traditional materials used.

stuhse

It would appear the damp here is rising damp ?. The source will always be there- its the ground it cannot be removed.  In modern houses it is kept at bay by installing a horizontal damp proof course just above ground level during its construction and this has been common practice for many years.  However many many houses were built before the idea of a damproof course was compulsory  or in older houses if has failed as appears to be the case here.  Once built it is of course very difficult (though not impossible) to install a horizontal damproof course retrospectively.  The next best solution is a vertical one which goes up the wall- essentially polythene with dimples on which allow the wall to breathe- allowing you to replaster. That would appear to be whats been done here ?  15 years ago there was a problem- work appears to have been done by professionals as evidenced by the sketch. Today there is no apparent problem ....