Damp On base wall

[James M]

HI All,
First post.. .
I have recently purchased a end of terrace two bed cottage (1890.s)
There is some damp signs that have been recognized at the base of the wall in some part of the down stairs.
There is underfloor heating that has a membrane when fitted (not by us)
I dont know how long the damp has been present as just purchased.
But it appears soft on the Gyspum plaster board and flakey in places. also get high readings on the meter. Its not a large room approx 10 sq meters
House has double glazing.
Some gutters to rear of property (not the image shown) wee leaking and going onto property.
Ive had a surveyor say it requires a membrane not a chemical injection. hack off 1 meter then fit the lathe membrane and plaster board over the top
my concerns are will this house bricks rot underneath as they said there is failed to no DPC causing rising Damp.
I am getting all gutters replaced.

Thanks

 

[housewinnie]

Check your outside ground height.

 

[James M]

Check your outside ground height.

Thanks
I did notice that the drain pipe was actually to the wall
I moved now as per Pic.
This part as per pics has soil pipe underground so cant dig too deep there also access to garden. But I am thinking around paremter of house dig down and placing stones.
Basically a better soak away

 

[housewinnie]

You could try digging down about a foot around the outside and renew gravel. Sometimes over time the gravel gets dense with soil etc

 

[housewinnie]

I would always start with the cheapest fix first

 

[Toby Newell]

Confused dot com, house bricks? I can only see stones in the photos, you also have bricked elevations that aren't shown?

The photos appear to still show leaking gutters with wet wall behind! Check again. Also photo shows random bricks, soil and vegetation above ground level with wet wall and algae growth! This is beyond a no brainer, re check gutters, remove bricks, soil and vegetation.

What do you mean by membrane? What membrane? You mean the UFH has a DPM underneath? Thats just standard practice! It should also have PIR foil insulation underneath that also functions as a DPM, UFH is very helpful in damp properties.

What do you mean the surveyor? From a damp company that sells stuff? He isn't just a surveyor then, he is mostly a salesperson.

And what do you mean lathe membrane? Sorry, for a person who is asking for help your OP is very brief, badly written and unclear!

You mean a membrane behind the lathe? This sounds very odd. You fit trickle membranes in cellars to an internal pumped perimeter drain.

I would go ahead with the new gutters, remove all the above ground height crap from the perimeter, run a dehumidifier, don't be stingy on the heating and wait a few months to see if it improves.

What stone and bricks do you have? Drilling a DPC might be helpfull, did the 'surveyor' specify why not?

Symbiosis is important, you have a DPM under the floor, so moisture forced to the walls, if you fit a DPC with dry sticks for example then the moisture will be retained in the first courses and the footings, in that case you might want to dig shallow french drains to allow those lower courses to drain moisture easier.

 

[James M]

Confused dot com, house bricks? I can only see stones in the photos, you also have bricked elevations that aren't shown?

The photos appear to still show leaking gutters with wet wall behind! Check again. Also photo shows random bricks, soil and vegetation above ground level with wet wall and algae growth! This is beyond a no brainer, re check gutters, remove bricks, soil and vegetation.

What do you mean by membrane? What membrane? You mean the UFH has a DPM underneath? Thats just standard practice! It should also have PIR foil insulation underneath that also functions as a DPM, UFH is very helpful in damp properties.

What do you mean the surveyor? From a damp company that sells stuff? He isn't just a surveyor then, he is mostly a salesperson.

And what do you mean lathe membrane? Sorry, for a person who is asking for help your OP is very brief, badly written and unclear!

You mean a membrane behind the lathe? This sounds very odd. You fit trickle membranes in cellars to an internal pumped perimeter drain.

I would go ahead with the new gutters, remove all the above ground height crap from the perimeter, run a dehumidifier, don't be stingy on the heating and wait a few months to see if it improves.

What stone and bricks do you have? Drilling a DPC might be helpfull, did the 'surveyor' specify why not?

Symbiosis is important, you have a DPM under the floor, so moisture forced to the walls, if you fit a DPC with dry sticks for example then the moisture will be retained in the first courses and the footings, in that case you might want to dig shallow french drains to allow those lower courses to drain moisture easier.

Sorry I am not very good a writing I get confused with letters and numbers.
The internal wall in the first picture has "Tide marks"
I was told before purchasing that it suffers from rising damp
So I thought best to get some opinions hence I ordered the Damp Survey.

Inside Property...
They said that there was no signs of a DPC on the this property and the brick work behind the plaster needs to have a membrane infornt the dot dab with platser finish.
They said most walls downstairs were sufferings with the tide marks and damp.
I must admit the marks were only at the base of the wall as per pic.
It did not smell muskie or damp in the house.
Surveyor said that he didnt like to use a chemical DPV on old properties and had better result with the membrane sheeting.


Outside The House
Stone Built house
There was obvious signs of leaking gutters and no obvious drainage for rain water.
Infact the pipe was resting on the wall and just rain water allowed to flow on the side of it
Yes there is defiantly work needs doing outside which we will do


Thanks for any advice.
Hope that makes sense

 

[Toby Newell]

Thats cool, I get confused and I don't have an excuse. I can see the damp, it doesn't look that bad, but then you don't know if it's new decor / plaster etc, to sell.
Yes, looks like rising damp.
Who did the survey? A guy who sells stuff? Or an independent?
Yeah, 1890, kind of the switch over period, the more rural the location the slower they were to adopt the latest features... was theoretically a legal requirement in London from 1875, lots of cottages don't have them until early into the 1900's.
Unkless the surveyor has x ray eyes this seems a bit odd and a bit of an overreaction tbh. Looks like minor rising damp at bottom only caused by crappy stuff going on oputside as you said and as shown in the photos.

My advice would of been to undertake remedial works to the guttering, drains and clear the above ground level crap from the perimeter, wait over the summer and reassess in 6 months.

Why does he not like a chemical DPC? because it's cheap and you can do it yourself for a couple of hundred quid? What harm can it do? Looks like you have stone with lime mortar, quite a durable combination. The ground is wet with poor drainage, if your surveyor was on the ball he would of suggested remedial works to the gutters / drains, wait and see, then dig a french drain. This will do much, much more to reduce the moisture level of the lower courses and is currently doing much more potential harm than fitting any chemical dpc.

Seems bogus to me, but mind you I am a total amateur, albeit one who has visited and worked on hundreds and hundreds of period homes all over the UK.

 

[James M]

Thank you Toby some useful info.
One thing that does puzzle me.

Is the internal picture of the damp.
Readings from a moisture meeting were taken did show damp.

But this wall (if i can explain right) is actually an internal wall not a side wall to outside world (so to speak)
It seperates the lounge from the kitchen.

The far left of wall would connect to the wall facing outside.

If that makes sense

 

[Toby Newell]

Thank you Toby some useful info.
One thing that does puzzle me.

Is the internal picture of the damp.
Readings from a moisture meeting were taken did show damp.

But this wall (if i can explain right) is actually an internal wall not a side wall to outside world (so to speak)
It seperates the lounge from the kitchen.

The far left of wall would connect to the wall facing outside.

If that makes sense

Rising damp wicks moisture via capillary action which can transport it over great distances from the source, you possibly have lime mortar which is very porous, you also have irregular sized 'bricks' ie stones and varying mortar course thicknesses, which looks lovely... however, say you had a particularly chonky mortar course just around or above ground level, then this would act like a big straw wicking moisture from the outside perpendicular to the outside wall end.

Lime mortar, especially in an irregular shaped stone and lime construction (which has a greater percentage of mortar bed) is very breathable and under normal circumstances will suck up this moisture and dissipate it over the large mortar surface area where it can evaporate naturally. Ideally you do not want to mess with that. Originally your walls would have been plastered with lime plaster and a breathable paint which would of allowed some of this moisture to also evaporate into the interior, any open fire would have whisked this humidity straight up the chimney and everyone was happy. Rising damp still may have been an issue, hence why every building is required to have one and has been required to do so for over 100 years, but the breathable nature of the construction and the draughts and open fires would of mitigated this to some extent.

This makes the surveyors advice all the more baffling. The issue appears to be there is poor drainage around the perimeter which means high hydrostatic pressure is forcing more water into the lime mortar course which then wicks along the course laterally and moves upward through the perps (vertical mortar lines) The replastering with modern gypsum which is less breathable than the original lime plaster, is probably not helping in dissipating this moisture and thus it is sitting at low level and possibly starting to suck up salts, which hold more water (if you scrape off the bubbled paint and you see mottled white deposits... < salts)

Prevention is better than cure, it's basic logic. You appear to have (check it hasn't been repointed in portland cement) a breathable lime mortar bed which is sucking up moisture and traversing the interior wall and showing up above your skirting. The best option is to reduce the amount of moisture available to track here. Secondly the option should be to make sure that any moisture that still manages to makes it through can spread quickly over a large surface area and evaporate easily and be removed from the home by good heating and ventilation.

Blocking this off is monkey with hands over eyes, as water will still be wicking up behind the membrane and slowly degrading the lime as it will have no means of escape to the interior (exterior has wind assistance, interior has higher heat assistance, both are useful in maintaining good breathability and evaporation rates)

The real issue is to reduce the hydrostatic pressure forcing water into your home, which you have identified can be helped by fixing the gutters and the drains and removing the flotsam and jetsam from around the perimeter.

You need to do this, pause and reassess in a few months time, things take time to dry out. I think your next step would be to consider digging shallow french drains around the perimeter to further drain the water if things don't improve.

If that doesn't sort it (it may take 6m to a year to do all of this and wait for results) then you might want to consider something like a dry stick DPC in that area only. It is not going to do any harm.

If all that doesn't sort it (pretty sure it will help a lot) then I would opt for the opposite of what the surveyor said! ie remove the modern gypsum and replace with lime plaster to allow what little rising moisture you have a means to spread over a larger surface area and evaporate easier, rather than congregating at the coldest and lowest point and sucking up salts into the gypsum which will only makes things worse.

You should get more opinions, but it's nice to have options. I am very skeptical of what the surveyor said as it makes no sense to me. If you told me he reccommends people who can do the job... then suddenly, praise be I would see the light, as for honest, helfpul advice, meh, I do not concur, but then I am a total amateur and I haven't seen the property.

You obviously posted here because your spidey sense was tingling, mine is too, as well as a feint whiff from the BS meter, I would certainly get another expert opinion and ask them to check if you have lime mortar or if someone has repointed with a harder and less porous sand and cement. I doubt your stone is going to rot.