Damp cases Feb ’21 London

17 Flats & 9 Houses

12 buyers, 6 vendors, 7 landlords, 1 owner occupier (Covid vaccinated).
Click for case name for survey illustrations and Survey Tips. See abbreviations below.

Summary for Feb ’21 London, damp surveys:

  1. Groundwater (rising damp) 0%,
  2. Rain 42%,
  3. Mains leak 12%,
  4. Vapour 77%,
  5. Hygroscopic salts (vapour) 15%,
  6. Previously damp-proofed (still damp) 70%.
casesymptomsproperty-typeprevious-damp-proofingRICS-PCA-misdiagnosisroot-causestitle 
102Abmtsvt0sivrmould-high-co2-slow-extractor-blocked-gutter
102Bbmtpvtsirvrrics-surveyor-unable-diagnose-rising-damp
102CmtpmtTvmould-under-flat-roof-radiator-imbalance
102Dmtmb0vmould-underfloor-heating-door-curtain-unducted-vent-into-loft
102Ebtpsvtsirvtreated-damp-resulted-in-rot-as-neighbours-gutter-blocked
102Fbmhdedsdrdrhdamp-proofing-despite-undrained-down-pipe-and-hygroscopic-salts
102Gbtmpcd00vlchurch-conversion-mould-condensation-and-leaks
102Hbetdrrfdry-lined-neighbour-drain-suspected-leak
102ItsvtTrtop-floor-flat-penetrating-damp
102Jbthpvs-trvhgarden-maisonette-with-interstitial-condensation-and-hygroscopic-salts
102Kbpvt-sirdlhlower-ground-floor-flat-damp-proofed-without-success
102Lmptvt1vmouldy-second-floor-flat-suspected-rain-water-from-roof-terrace
102MmtpmdTvtop-floor-mould-condensation-suspected-flat-roof
102Nbts0vrising-damp-not-even-close
102Obmme0vsuspect-penetrating-damp-exposed-render-insufficient-ventilation
102Ptvt1hhygroscopic-salt-calcium-chloride-first-floor
102QbthpvtTvsuspect-penetrating-damp-first-second-floor-flat
102Rbpvs-scrdrvcavity-membrane-lower-ground-floor
102Sbmpcve-sivrdamaged-from-damp-proofing
102Tbvtsirdvrics-misdiagnosed-rising-damp
102Ubmet0sdrrvrics-missed-blocked-gulley-dry-lined
102Vbmvt0sdrtvpca-contractor-misdiagnosed-rising-damp-dry-cellar
102Wpvs1rvrics-able-to-make-assumption
102Xbcvtcrrrics-rising-damp-claim
102Ybcmva0vlrcondensation-leak
102Zbhvs-trdvdamp-proofed-lower-ground-floor
Case studies for February 2021

Explanations & abbreviations

Symptoms

b = damp at base of the wall at or near ground level
m=mould,t=damp at top of wall
p=damp in patches
c=crystallised (surface) salts
h=hygroscopic salts

Property type

Period | Attachment | Floor if flat

Period

p = Pre-Georgian
c = Church or similar conversion
g = Georgian
v = Victorian
e = Edwardian
t = Twenties, Thirties (1920 / 30’s)
m = modern (post war)

Attachment

t = Terraced
e = End of terrace
s = Semi-detached
d = detached

Flats – floors 

Based on susceptibility to damp i.e. ground or roof.

– = lower-ground floor or basement
0 = ground-floor
# = floor number
9 = top floor (exposed to roof)

Previous damp proofing

i = Injected thixotropic siloxane cream or silicone into base of wall as “DPC”
s = Slurry used to hide symptoms of damp, with impervious plaster.
d = Dry lined, also used to hide symptoms of damp, by separating plaster from wall.
t = Tubes, mainly Dutch, such as sold by Frank Schrijver, tends to also include damp hiding slurry.
0 = No damp-proofing.
– = N/A – Not appropriate, perhaps because a flat without a ground-floor.

RICS / PCA (contractor) misdiagnosis

It is normal for a buyer to instruct a RICS surveyor to inspect a property during the process of buying it. Most RICS surveyor are good.

Some inexperienced surveyors will misdiagnose a high damp meter reading at the base of a wall as Rising Damp, without any additional evidence. It is for this reason that such a high proportion of properties have been damp proofed, yet as statistically about 70% (Damp Surveys – London), of those same properties have ongoing damp issues.

PCA contractors specialise in a specific field. If they are instructed to quote for Rising Damp, then they will do that, without looking for evidence (other than a high damp meter reading) or for other sources of dampness. How can blame them, they are incentivised to find Rising Damp.

r = RICS surveyor
p = PCA contractor

Root cause (as opposed to symptoms)

g = Groundwater
r = Rainwater
l = Mainswater
v = Vapour
h = Hygroscopic salts (vapour)

Leave a Comment

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.