How do I know if I can trust my damp surveyor?

daveyjp

Immediate jobs are.
Move the shed, clear out the holes on the airbricks using wire coathanger or garden cane.

You have a PM re surveyor in West Yorkshire.

twopenny

I've had 2 occasions of damp coming through brick right through to the plaster. It's surprising what a mess a small thing can make in this way. Happened to me where a series of small things created a lot of damp soaking thorugh the bricks into plaster and wood in a house that had always been dry..

There are some small things you could try yourself in the meantime.

The shed is trapping moisture and cold air against the wall as has been said. It's also against the air brick which won't help air circulation in that small space.

Where the stone is exposed in in your 6th photo on page 1, does it feel damp? Does the plaster feel damp? If so can you start to dry it out from the inside. The stone won't dry throughly until we get some really hot dry weather (please soon) but you need to allow it to get to the stone but it can be done, I cleared my wall and loose plaster to allow it to dry. Took most of a hot summer but it did dry and then I could repair.

The internal air vent is almost closed. You really need a new one, perhaps one which you can open and close so in cold months if there's a draught you can close it temporarily, when not the warmer air from the house can go through. These are cheap as chips.

Is that chippings up to the wall or something sealed? If it's not sealed have a dig along there with a trowel and see what is underneath. There doesn't seem to be any drainage along that wall and water could be running between it and pooling at the side even though you can't see it.

With the eternally wet winter we've had this has probably shown up a weakness. So a mixed blessing, you can do something about it.

Internally modern paints won't let the moisture or warm air through and it's trapped. Also happened to me.

Good luck. See what you can find.

Arghbloodyhouse

Thank you everyone for your help. I'm only updating because I'm annoyed. I spoke to the damp surveyor finally and tried to get an understanding of where he thought the water was coming from. He said the "rising" damp was travelling horizontally through the wall due to the fact the house is on a hill and therefore the ground level slopes upwards on that side of the house. I asked if he thus wanted to do a DPC that travelled vertically up the side of the house and he said he wanted to do two DPCs - one vertical and one horizontal. I don't know if that's even a thing? Anyway I asked about alternatives to chemical dpc (as two surveyors have now said they don't think the house has a DPC) and he just said "we don't offer those". Sure, but I have already paid you for a survey becaue you said you were a surveyor. I don't care whether you want to upsell me or not!

Grrr! Anyway. I can't move the shed alone unfortunately and it being lockdown it's just me (5'4 with the upper body strength of an 8 year old!) so I'll have to wait until I can get help with that. In the meantime, I called a chartered surveyor who told me I had to speak to a damp specialist and passed me onto someone who is now doing a 'free' survey (suspect...) I'll let them do it to see if it's any use but will be calling other specialist surveyors too. 

Thank you @daveyjp the surveyors you recommended are a little far from me (I'm just outside Greater Manchester, really) but if all else fails I'll call them in anyway!

JackR09

These accreditation’s such as ‘Which’ mean very little as couriervanman said. Do the most research you can and trust your instincts.

ccluedo

This company seems to have a good reputation anywhere I have seen them mentioned and cover most of the UK as far as I know.  I believe the guy can be a Damp Survey and Installation companies worst nightmare Not just old houses they deal with either. I don't imagine they will be inexpensive but could be money well spent and  might even just be worth an email or call for some initial (hopefully free) advice.
https://www.heritage-house.org/
From their site
"our Timber and Damp surveys turn the myth of rising damp on its head.  We'll tell you if your house really IS damp, and why. How to deal with it, how to maintain it, and what it'll cost."
Also worth a read since particular to your issue...
https://www.heritage-house.org/damp-and-condensation/the-fraud-of-rising-damp.html