Damp courses / Render skirtings

Are these skirts outside or inside?

If they are inside, do they go below the floor? I don't believe they had damp courses in those days but used air bricks with a space under the flooring instead.

If they go around the outside, then obviously they serve as watersheds.

Almost certainly an attempt to counteract 'ground splash' - if you look at walls in heavy rain, the lower 6" or so gets wet from rain splashing up from the surrounding ground surface. Failing that explanation it COULD just be decorative, or perhaps repairs to spalled brickwork caused by the ground splash or rising damp below a DPC followed by frost. I did have a house a few years ago (built 1898 iirc) that hade standard sized roof slates embedded in a plinth such as you describe, but wether it was original or a later attempt at damp control was a matter of conjecture.

Houses in the period you mention will pretty certainly have some form of dpc - earlier ones being slate and later ones bitumin ( though my 1903 house breaks that rule by having bitumin). Both fail over the years from slight movement of the structure.

In the case of my 1903 Edwardian house, again rather unusually, the foundations are mass poured concrete, BUT the original DPC was put in AT ground level directly on the footing concrete, and not at the more usual 6" above ground level.

Andrew Mawson

Snip

Snip But don't bet on having a damp proof course, my 1906 house, as originally built, had no damp proof course, suspended wooden floors (and no air brick) and the foundations are just a widening of the wall to about double width (becoming 18 inches) but only six inches deep, Oh and the other half of the house has flint foundations. (I'm only 2 feet above the winter ground water level!). I would suggest you don't have a DPC as that wouldn't work with the render foot! The render foot is common around here to prevent water splashing as previously noted , it is often tarred, as well to increase the proofing.

The Q

They are external "skirts" ( dunno if that is the right term)

What I don't get is if the are supposed to be effective, won't they need to be waterproofed somehow ? If they are a lime mortar, and don't have an internal vertical seal, won't they be of limited benefit ?? And if there is a physical dpc, won't they bridge it in exactly the way we are told you shouldn't ??

"coherers"

I am 99% certain the plinths /skirtings here are original, as every house around here has them and they seem to be identical between properties. I have seen horizontal damp courses which use offset layers of slates between two courses of bricks. I wasn't clear, did your 1898 house have this, or did it ( also) have slates embedded *vertically* in the plinth to give protection from damp entering horizontally????

Reason I am asking is not purely academic. I have inherited a small property (not the house with the render skirtings) which had no dpc - and which suffered from rising damp. However, I understand that the external render ( no skirt, just flush) , if restored, will bridge the chemical dpc I had injected, and I was wondering if the use of a skirting with embedded slates / bitumen layers was a recognised technique I could apply. The alternative I believe suggested by the dpc company was a "bell drip", but this will still result in a layer of render bridging the dpc underneath the drip, if I am not mistaken. Putting a waterproofer in the render would invalidate the dpc guarantee, I am told, so I was wondering if there was a physical technique.

Thanks

"coherers"

It's a heck of a long time ago to remember ( 29 years !) BUT IIRC in the

When moisture is absorbed into lime render, I'm told it is only drawn into the first 2mm, so if the skirt is thicker then that then it should help. 2mm seems very little to me, but who am I to argue with some limey?

Anna

-- ~~ Anna Kettle, Suffolk, England |""""| ~ Lime plasterwork, plaster conservation / ^^ \ // Freehand modelling and pargeting |____|

I saw some recommendations for building materials for houses on flood planes somewhere on one of the government websites a year or so back. One of the comments there was to suggest the use of lime plaster, as it apparently is much less likely to need replacing after being submerged.

Nope. Lime render absorbs damp all the way through. But then dries out again without damage.

This image of lime mortar like a sponge isn't right and in practice lime mortar doesn't absorb damp all the way through. I've removed soaking wet lime mortar and a little below the surface it is dry as a bone. I suspect that water soaks into the surface and the clogged pores then act as a buffer inhibiting more water from getting in.