Leaky house. Would a surveyor help?

couple of hundred notes typically for a very good opinion.

Do you mean surveyors in general give very good opinions or that I'd get a bad opinion for £100 ;)

People claiming damp expertise are very variable, there's no shortage of unsuitable recommendations & diagnoses, so I'd be rather hesitant to get a damp expert in, and even more so a non-damp-expert. I'd say your best bet is to learn about damp in old houses, a good place to do that is the period property uk forum (assuming its still running). The sort of techniques used on modern builds are often not suited to old houses with no dpc, soft bricks, etc.

Damp near ground is more often condensation than rising damp.

NT

Both

There is cavity insulation and there is cavity insulation. You may also have gutter problems which you should check out before spending money and time trying to find defects elsewhere. I'd hazard a guess the penetrating damp is due to either pointing problems or you have water soaking into the brickwork from the driving rain and traversing the outer and inner leaves of the wall with soaking across the cavity insulation. First port of call a recommended builder/bricklayer to have a look at the pointing. If its porous brickwork then Sovereign Chemicals do a water repellant spray you can apply with a long lance from the ground. As to the rising damp if thats what it is, If there is a damp proof course present it may be bridged by render or soil and providing a "wick" effect. Have a good look round and check for bridged bits. The cavity insulation could also be causing problems if it is creating a hidden bridge across the dpc. This might require cutting a brick out to allow internal inspection of the cavity low down section.

I think that whoever does it, you need to do a bit of dismantling - by removing a few bricks - to see what's going on. Chances are that it's not rising damp, but rather water being absorbed by the outer skin and transmitted to the inside. This often happens when cavity wall insulation is pumped into cavities which have been bridged by mortar dropped onto the ties. Without the insulation, the water just evaporates off the ties, but the insulation stops that from happening - so the water is transmitted to the inner skin.

In message , Another Dave writes

Get the professionals in to quote for work required and price, then DIY

obvious

Get an SDS drill and drill exploratory holes from the inside, you should be able to patch them from the inside with ready mix cement, or temproary plywood covering whilst investigation goes on.

You can take your time to find out whats wrong.

And with that knowledge ask a surveyor more intelligent questions.

I've had this house 4 years and been DIYing every day but there are still many unknowns.

Try a pair of 200 year old cottages knocked together after WW1 !