Damp cases Feb '21 London

Contents hide

1 17 Flats & 9 Houses

2 Explanations & abbreviations

2.3 Previous damp proofing

2.4 RICS / PCA (contractor) misdiagnosis

2.5 Root cause (as opposed to symptoms)

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:

Groundwater (rising damp) 0%,
Rain 42%,
Mains leak 12%,
Vapour 77%,
Hygroscopic salts (vapour) 15%,
Previously damp-proofed (still damp) 70%.


102A	bmts	vt0	si	–	vr	mould-high-co2-slow-extractor-blocked-gutter
102B	bmtp	vt	si	r	vr	rics-surveyor-unable-diagnose-rising-damp
102C	mtp	mtT	–	–	v	mould-under-flat-roof-radiator-imbalance
102D	mt	mb	0	–	v	mould-underfloor-heating-door-curtain-unducted-vent-into-loft
102E	btps	vt	si	–	rv	treated-damp-resulted-in-rot-as-neighbours-gutter-blocked
102F	bmhd	ed	sd	rd	rh	damp-proofing-despite-undrained-down-pipe-and-hygroscopic-salts
102G	btmp	cd0	0	–	vl	church-conversion-mould-condensation-and-leaks
102H	b	et	d	r	rf	dry-lined-neighbour-drain-suspected-leak
102I	ts	vtT	–	–	r	top-floor-flat-penetrating-damp
102J	bthp	vs-	t	r	vh	garden-maisonette-with-interstitial-condensation-and-hygroscopic-salts
102K	bp	vt-	si	rd	lh	lower-ground-floor-flat-damp-proofed-without-success
102L	mpt	vt1	–	–	v	mouldy-second-floor-flat-suspected-rain-water-from-roof-terrace
102M	mtp	mdT	–	–	v	top-floor-mould-condensation-suspected-flat-roof
102N	b	ts	0	–	v	rising-damp-not-even-close
102O	bm	me0	–	–	v	suspect-penetrating-damp-exposed-render-insufficient-ventilation
102P	t	vt1	–	–	h	hygroscopic-salt-calcium-chloride-first-floor
102Q	bthp	vtT	–	–	v	suspect-penetrating-damp-first-second-floor-flat
102R	bp	vs-	sc	rd	rv	cavity-membrane-lower-ground-floor
102S	bmpc	ve-	si	–	vr	damaged-from-damp-proofing
102T	b	vt	si	rd	v	rics-misdiagnosed-rising-damp
102U	bm	et0	sd	r	rv	rics-missed-blocked-gulley-dry-lined
102V	bm	vt0	sd	rt	v	pca-contractor-misdiagnosed-rising-damp-dry-cellar
102W	p	vs1	–	r	v	rics-able-to-make-assumption
102X	bc	vt	c	r	r	rics-rising-damp-claim
102Y	bcm	va	0	–	vlr	condensation-leak
102Z	bh	vs-	t	rd	v	damp-proofed-lower-ground-floor

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)

Damp cases Feb ’21 London