FTBs building survey found 'rising damp' in 1930s semi - likely causes and best next steps?

Lunielumps

Hello, 
We're FTBs and had our building survey back for a 1930s semi in Manchester, which among other things (needs rewiring, windows don't have lintels etc.) they have identified "rising damp". They used moisture metres and found damp on the lower sections of all ground floor external and internal walls. There are also some tide lines on the ground floor wall next to the bay window. Other than that there is no damp smell and no mould (although all walls were painted white before putting it on the market about 9 months ago to disguise any issues). It is an ex rental house that hasn't been taken care of, and has been vacant for the best part of a year now which cant have help having no heating on ventilation. 
The walls are cavity construction, with potential evidence of CWI having been injected in at some point. There is a bitumen DPC which the surveyor has labelled as 'failed'. There is also a tarmac drive which gets very close to the DPC in places, definitely less than the recommended 150mm at the front of the bay. 

Where should we start when trying to budget for works to solve these issues? Potential CWI removal? adjusting the tarmac drive to move it away from the DPC and installing a french drain? potential for rotting beams under the floor? Replacing the 'failed' bitumen DPC?
Also are there any other likely causes that could be contributing? 
Any advice and knowledge much appreciated!

IamWood

The general survey always contains some scarring stuff. Meter reading sometimes is misleading. It may or may not have a damp issue. If you are really concerned you may instruct a specialised surveyor for it, which may be expensive. 

Did you call your surveyor to discuss the concerns?

FreeBear

Lunielumps said: Where should we start when trying to budget for works to solve these issues? Potential CWI removal? adjusting the tarmac drive to move it away from the DPC and installing a french drain? potential for rotting beams under the floor? Replacing the 'failed' bitumen DPC?
Also are there any other likely causes that could be contributing?

How good are you at DIY ?

With a pickaxe and possibly a 9" grinder with a diamond disc, a weekend of graft will see the ground level reduced. You won't get 150mm below the DPC without exposing the footings. So I'd suggest cutting the paving ~200mm away from the wall and put a layer of gravel down.

The DPC will not have "failed" unless it has been subjected to some pretty serious damage like driving a tank through the walls. By the sounds of it, you have already identified the most likely culprits of damp - It has been a cold wet winter, so no real surprise that the house has elevated damp levels. Open the doors & windows during the summer, and put the heating on over winter, and the damp will subside. Unless the house is in an exposed location, the CWI is unlikely to contribute to any perceived damp. Depending on the type of CWI, it could be very expensive to remove. So save your money on CWI removal and any questionable damp "cures" (injected DPC, waterproof render/plaster, etc).

Spend your money on a rewire (if it is really needed), putting lintels in, and decorating.

I've got a late 1920s semi of similar construction...

stuart45

Is there a problem with the brickwork over the top of the windows?  A lot of houses of that period had brick soldiers over the frames, and concrete lintels on the inner skin. However the soldiers were tied into the lintels with wall ties. I know from experience that it makes a very solid job, having had to remove some.

Lunielumps

stuart45 said:

Is there a problem with the brickwork over the top of the windows?  A lot of houses of that period had brick soldiers over the frames, and concrete lintels on the inner skin. However the soldiers were tied into the lintels with wall ties. I know from experience that it makes a very solid job, having had to remove some.

Hi Stuart, thanks for your reply. the surveyor said: 

"Movement was noted over the front main bedroom window to both the wall and window frame, this appears to be due to a lack of an appropriately fitted lintel in this area. This cracking could be re pointed however some cracking may occur again, the only long term solution would be for a new lintel to be inserted over this opening under professional supervision."

The diagram you included did look like the brickwork above the window, with the string of vertical bricks. Do you think the cracking sounds like something to worry about or do you reckon repointing might be sufficient?

IamWood

Lunielumps said:

Hi Stuart, thanks for your reply. the surveyor said: 

"Movement was noted over the front main bedroom window to both the wall and window frame, this appears to be due to a lack of an appropriately fitted lintel in this area. This cracking could be re pointed however some cracking may occur again, the only long term solution would be for a new lintel to be inserted over this opening under professional supervision."

The diagram you included did look like the brickwork above the window, with the string of vertical bricks. Do you think the cracking sounds like something to worry about or do you reckon repointing might be sufficient?

Have you looked around in the area for the other similar houses. It might be a common issue for the properties at that time. I know my house (1930) has some cracks around the windows. I simply repointed them.

stuart45

Lunielumps said:

The diagram you included did look like the brickwork above the window, with the string of vertical bricks. Do you think the cracking sounds like something to worry about or do you reckon repointing might be sufficient?

It depends on how bad the cracks are and what is causing them. The diagram is an example of how lintels were often formed back then, and a surveyor might mistake this for having no lintel in place on the outer skin. 
However they were not all done like this, and some of them just relied on the timber window frames to take the brickwork. When replaced with plastic there could be a problem.

FreeBear

stuart45 said:   The diagram is an example of how lintels were often formed back then, and a surveyor might mistake this for having no lintel in place on the outer skin. 
However they were not all done like this, and some of them just relied on the timber window frames to take the brickwork. When replaced with plastic there could be a problem.

Having had a window replaced recently, the outer soldier course is not tied to the internal concrete lintel. So had a steel fitted before the window went in - By removing a couple of bricks at the to of the opening, there was just enough room to slip the steel in. Saved on having to remove the soldier course and kept the cost well down.

It was fairly common round here to put a wooden frame in and then build the outer leaf above without any additional support in the 1920s, 1930s, and some builders were still doing it in the 1970s.

Slithery

Lunielumps said:

 they have identified "rising damp"

No, they haven't. That's just what they want you to think...

https://www.heritage-house.org/damp-and-condensation/the-fraud-of-rising-damp.html

https://www.wcp-architects.com/the-rising-damp-myth/

stuart45

FreeBear said:

stuart45 said:   The diagram is an example of how lintels were often formed back then, and a surveyor might mistake this for having no lintel in place on the outer skin. 
However they were not all done like this, and some of them just relied on the timber window frames to take the brickwork. When replaced with plastic there could be a problem.

Having had a window replaced recently, the outer soldier course is not tied to the internal concrete lintel. So had a steel fitted before the window went in - By removing a couple of bricks at the to of the opening, there was just enough room to slip the steel in. Saved on having to remove the soldier course and kept the cost well down.

It was fairly common round here to put a wooden frame in and then build the outer leaf above without any additional support in the 1920s, 1930s, and some builders were still doing it in the 1970s.

Construction methods vary quite a bit around the country, especially those built before the mid 60's. You were quite lucky to have one that wasn't tied to the lintel. One of the issues with a composite brick/concrete lintel is the rusting and expansion of those thick twist type wall ties that were often used. There were other methods of support used such as re bar in the holes of extruded bricks. You are correct in saying that the method of using solely  the timber frame window as support was still being used in the 70's. I was on a Laing's site in the hot summer of 76(getting attacked by Ladybirds) where the frames had brickwork in stretcher bond straight on top of the frames with the first 3 being reinforced with brick tor. 
However with the introduction of the Catnic lintel in the early 70's it was much less common in all but the cheaper housing.
Even before that Dorman long used to make a steel lintel that sat on top of the inner concrete lintel, and then came down and over the frame in a similar way to a catnic.

Lunielumps

IamWood said:

Have you looked around in the area for the other similar houses. It might be a common issue for the properties at that time. I know my house (1930) has some cracks around the windows. I simply repointed them.

Thanks Iamwood, it looks like next door has done some repointing on the brickwork above their master bedroom window, and had the window replaced - if a lintel had been added to theirs would i be able to tell from the outside?