No DPC & Damp - shock horror

[LD84]

I’ve encountered a few issues with the property I recently purchased that require prompt attention:

 

• Air bricks blocked by paving on the rear elevation – I plan to expose these as soon as possible.

• No visible damp-proof course (DPC) – Despite the cavity wall construction (albeit very narrow), I haven’t been able to locate a DPC. Given this is a bungalow, this is a bit unexpected.

• Retrospective DPC installation – Has anyone had experience installing a physical DPC after construction? I’d appreciate any insights or recommendations or best practices. 

[Redbeard]

Your 1st point possibly suggests to me that the external ground levels are no longer where they used to be, and possibly that the ground surface is *harder* than it used to be, allowing more splash-up.

 

Many many houses have no dpc and no significant damp issues.

 

Your title suggests you *do* have damp probs, but can you give us more detail?. 

 

My own experience with inserting a dpc is it is a hell of a lot harder than you think (I thought) it was going to be. A lot can depend on the depth of mortar joints.

 

I am absolutely convinced that a huge number of the injected dpcs one sees were never necessary in the first place. The attitude of many Building Societies and public sector lenders/grant-givers, in the 1980s particularly, led to (I would guess) hundreds of thousands of installations of injected dpcs in buildings which were not damp.

 

More context please Incl. pics of possible, and we can get more specific.

[LD84]

11 hours ago, Redbeard said:

Your 1st point possibly suggests to me that the external ground levels are no longer where they used to be, and possibly that the ground surface is *harder* than it used to be, allowing more splash-up.

 

Many many houses have no dpc and no significant damp issues.

 

Your title suggests you *do* have damp probs, but can you give us more detail?. 

 

My own experience with inserting a dpc is it is a hell of a lot harder than you think (I thought) it was going to be. A lot can depend on the depth of mortar joints.

 

I am absolutely convinced that a huge number of the injected dpcs one sees were never necessary in the first place. The attitude of many Building Societies and public sector lenders/grant-givers, in the 1980s particularly, led to (I would guess) hundreds of thousands of installations of injected dpcs in buildings which were not damp.

 

More context please Incl. pics of possible, and we can get more specific.

Thanks Redbeard. 
 

Sorry for not making it clear - I have damp on the elevations where the airbricks are covered or missing. Additionally, appears I have a rotten joist near the damp but I haven’t inspected further. One of my jobs is to lift all the boards and check the condition plus void depth once Mrs D is comfortable. 
 

If I decide the DPC is worth it, what did you use to rake the joints and how much did you do at a time? Is 1m safe or should I do less? 

[ProDave]

10 hours ago, LD84 said:

Sorry for not making it clear - I have damp on the elevations where the airbricks are covered or missing. Additionally, appears I have a rotten joist near the damp but I haven’t inspected further. One of my jobs is to lift all the boards and check the condition plus void depth once Mrs D is comfortable. 

If you have damp on the walls where the air bricks are covered, and no damp on the walls where the air bricks are exposed and clear then you have answered your question.

 

It is very likely the walls are adequate in themselves, but the wall where the air bricks are covered the ground level is too high and bridging the DPC that is probably there.  Solution, reduce the ground level and expose then clear out the air bricks.

 

Post some pictures?