Damp around window

[Hugh Jaleak]

I have a problem with damp in the property, wallpaper peeling and black mould appearing. Wall seems wet to touch especially after rainfall, so suspect penetrating damp. I have lifted floorboards, although pavement externally appears to have bridged the slate DPC, the joists are dry with no apparent rot, other than the joist under the partition wall on R/H side of 2nd picture. (Between living room and porch)

Window was replaced with current uPVC frame circa 2002, replacing a wooden casement type frame. (The original windows were set in stone mullions, unfortunately previous occupier had these removed.)

Damp problem has been present since 2000 when I purchased, so far have applied 'Thomsons Water Seal' and replastered, which has brought brief respite. Any advice on best way forward to try and remedy this please?

 

[catlad]

I would get the hose pipe out and check the window was not leaking first.

 

[GaryGarden]

I would get the hose pipe out and check the window was not leaking first.

As above and check your gutters are clear, if full of debris they can over spill into the cavity running down until the water hits an obstruction like a lintel above a window, it will then flow down the sides of the window within the brickwork.

 

[Hugh Jaleak]

Cheers chaps, but I can assure you there's no cavity (9" solid walls), and gutters are clear. I am assured the window isn't leaking, there are no puddles internally when it's raining.

 

[ree]

Water test again, only you observe inside, and someone else plays the hose outside.
Lightly spray the w/frame and the brickwork up above the soldier course.

The brickwork looks to be in good condition - is the pointing? Is that a drip hood just above the soldier course?

Obviously poor brick re-installation above and just below the w/frame.
Elevation lower left, bottom course, some bricks are perished.

When last you re-plastered, did you use render or gypsum?

Perhaps strip all the paper off in that room.
Remove rad, and check the back of the front skirting board.
Knock off all damaged plaster to wall and reveal(s).
Now water test as above.

Observe as water drips off the PVC cill.
Now look for moisture or darkening of the interior brickwork and beds. It might take a while.
Moisture typically enters by capillary action.

Maybe cut out the damaged joist? Did you test probe the joist tails in the brick pockets for damage?
The air bricks and the joist tails should be seated on the DPC course.

Perhaps check for damp on the hall side of the wall/partition?

 

[GaryGarden]

Cheers chaps, but I can assure you there's no cavity (9" solid walls), and gutters are clear. I am assured the window isn't leaking, there are no puddles internally when it's raining.

If you don't have a cavity as such then the house is probably pre 1920's but there is still a gap albeit only about 10mm, however if your gutters are clear then this discounts the ingress there.

 

[stuart45]

A lot of people have had damp problems with solid 9 inch walls in recent months due to the wind driven rain. You might need to look at the pointing by the frame.
Damp walls are colder, so they attract condensation as well.

 

[ree]

stuart45, Damp problem has been present since 2000.
The damage in the pics has also been present, i'd say, for at least a few years.

GaryGarden, The wall is full of headers. Its a pre-1914 house.

 

[stuart45]

Houses were still being built with Flemish bond facework 9 inch solid up to the mid 30's.

 

[ree]

They are two different points.

1 Headers would indicate a solid non-cavity wall.
2 Based on features, and points of style, the house is pre-1914 - nothing to do with the headers.

 

[stuart45]

There are a lot of Victorian houses with cavity walls built in Mock Flemish with snapped headers. Headers are not always a sign of a solid wall.

 

[john4703]

There is a cable running down the wall and entering the building. On the inside photo it seems to be where the damp is. How is it installed? I like to see a loop of cable below the entry point to stop any water that runs down the cable entering the building. I have twice seem coax cable damaged and water running inside it to enter the building. It might be worth checking that cable.

 

[Hugh Jaleak]

House was built in 1896, date stone on house further down gives it away. Cable in question is BT line, it enters between window frame and wall, good wedge of silicone around it to seal it.

Had floorboards up earlier today, large amount of dust/crud/cobwebs etc under there, it's all dry and dusty which indicates to me no damp. Also dose of ant powder around edges of room at base of skirting is still very much dust, damp is at a higher level all along the wall. Damage at base of wall (near porch) are replacement bricks where an iron boot scraper used to be inset into the wall.

Some tiles inserted into brickwork above the soldier course, so would assume these are for drip hood. Replastering was done with a Carlite bonding undercoat. Damaged joist is under partition wall between living room and hallway, not too easy to remove! Joist tails appear to be sitting on a slate DPC, but air bricks are a course above DPC level, seems to be same on the whole terrace.

I can pretty much guarantee (provided we have a dry Summer!) the wall will dry out a treat, once we get a decent drop of rain it'll get damp again. So I suspect soaking the brickwork will show water ingress through the wall, so looking for a (not too obtrusive!) solution to fixing it! Maybe worth noting a number of the neighbours have had the front walls either injected with a chemical DPC or rendered.....

 

[stuart45]

Solid 9 inch walls will allow water through with enough driving rain. Some people render them, but this can trap moisture inside unless lime render is used. Carlite soaks up the moisture and holds it, unlike lime plaster which allows the walls to breathe.
On older properties with solid walls it's often more about managing the moisture than completely stopping it getting in.
If it needs repointing get it done with lime mortar.

 

[Flyboytim]

It appears that the ground level of the hard standing at the front has been built up to the airbricks. These bricks are to provide through ventilation to the underfloor space.

The original DPC is likely to be in the mortar course between the top of the airbrick and the course above.

There is insufficient height between the ground level and the brickwork above the DPC to prevent splashback, which tends to keep the external brickwork above the DPC damp, which in turn will keep the inner wall cold and liable to a recurrent condensation problem.

Because the DPC is a barrier to water, water repeatedly splashed above the level of the DPC soaks into the bricks, and they can remain cold through evaporation and damp, with the dampness affecting the inner skin of brickwork too, and conducting away heat from the interior more effectively than dry brickwork could.

The ground level within about 300mm of the wall should be reduced by a sufficient depth that a new gravel layer over the soil is at least 150mm below the DPC to prevent splashback and to drain away rainwater. The airbricks should be cleaned to remove any debris.

Internally there is not sufficient air movement, and the wintertime heating levels are possibly intermittent and varying between cold and warm, encouraging condensation on cold walls.

Before doing any remedial work, strip off the wallcoverings and allow an unheated fan to play air over the wall. If the plasterwork is sound, clean thoroughly during dry warmer weather and allow to dry out. Apply a mist coat (diluted with water) of contract emulsion, not vinyl, and then covering coats of the same, allowing to dry between coats. Look for any deterioration of the paint coat over time with bubbling, flaking and fluffy or dusty salt deposits forming. If these appear, the plaster coat will require treatment, usually replacement.

The wall will dry off during the spring months, and appear to stay dry probably until October, since this is the usual pattern of condensation in the home.

Try to heat the home to within a small range of temperatures - with a minimum of 15 deg C, rising to 18-20. Use fans to prevent cold spots, damp cupboards and wardrobes etc. Turn heat up in very cold weather, but return to a basic thermostatted regime when milder.

Don't follow the pattern of turning the heating off at night, on high in the morning, off during the day, and on high again in the evening. This will heat the air and not the walls and windows to the same degree, and condensation will result, getting worse over the winter, leading to damage to wallcoverings and plasterwork.