Damp - What type of tradesman should I use?

illusionek

Hello

I am in the process of purchasing my first house. I got results of survey and there are some actions I need to take to rectify issue with damp once I move in. Unfortunately I have no DIY skills nor tools so will need to ask specialist(s) to deal with below issues. However I am not sure who I am looking for? Do I need separate tradesmen or there is some sort of general builder who deals with these issues? Below jobs seem to be quite small to be allocated to separate tradesmen but then I am not really sure. I have been renting so far so never had to call anyone.

I would be very grateful for an advise who I am looking for.

Also was wondering if anyone can let me know what I should expect to pay? I am after rough estimation. The property is in Bexley, Greater London.

This is 3-bed Victorian semi-detached house, built ca 1890, size approx 100m2/1076sf.

External ground levels reduction – external ground levels are above the damp proof course causing dampness. They need to be reduced to be about 150mm (two brick courses) below the damp proof course and then the channel to be filled using pea-shingle but not above the damp proof course. High ground levels exist along the length of the main flank wall, across the main rear wall and along the length of the kitchen flank wall up-to the side door.

Additional airbricks are required within the main flank and rear walls to allow sufficient ventilation for suspended floors.

There is no ventilation or not enough in the roof void/loft. Most likely it requires some tile vents or a combination of ridge vents and tile vents but this would need to be properly assessed.

There are two chimney breasts that require external ventilation. I presume they would need vents on both ground and first floor level.

Many thanks for all help!

tonyh66

you need a general builder who does roofing and chimneys, or a roofer who would install airbricks. You could probably dig the ground level down below damp course yourself if your able bodied. Dunno how much, probably an arm and a leg seeing your in London.

illusionek

I could possibly dig the ground level down but how would I recognise the damp course, especially that the house is rendered? Never seen one before.

TheCyclingProgrammer

The render should stop above the damp proof course and have a drip bead. The DPC, if there is one, should be identifiable from a thicker mortar line between the brick courses. If the render is down to the ground then that also needs to be dealt with as it will be bridging the DPC too.

FreeBear

TheCyclingProgrammer wrote: »

The DPC, if there is one, should be identifiable from a thicker mortar line between the brick courses.

Bearing in mind that this is a Victorian property, the DPC could be a layer of bitumen, a thin layer of slate, or a course of engineering bricks. The first two would be identified by the thickness of the mortar joint, whilst the engineering bricks would be a different colour.

That said, a previous owner may have had a DPC injected, in which case there may be a row of holes filled in with mortar along each wall.

When digging down, be careful not to go too deep and expose the footings - You'll know when you get that far down as the brickwork will step out a little.

illusionek

Many thanks for your answers, I will trying lowering external ground myself when I get the keys to the property.

How long before I should start seeing effects of this work? I just want to make sure that I do not wait for too long before I get professional if I screw up or if I was advised incorrectly and there is a different reason for dampness.

SG27

illusionek wrote: »

Many thanks for your answers, I will trying lowering external ground myself when I get the keys to the property.

How long before I should start seeing effects of this work? I just want to make sure that I do not wait for too long before I get professional if I screw up or if I was advised incorrectly and there is a different reason for dampness.

I would give it at keast 6 months after reducing the ground levels.

Annie1960

illusionek wrote: »

Hello


External ground levels reduction – external ground levels are above the damp proof course causing dampness. They need to be reduced to be about 150mm (two brick courses) below the damp proof course and then the channel to be filled using pea-shingle but not above the damp proof course. High ground levels exist along the length of the main flank wall, across the main rear wall and along the length of the kitchen flank wall up-to the side door.

I'm in St Albans and had a similar job done last year for aroun £300. Dug out along the back of the house and added pea shingle. Simple job for a general builder.

Additional airbricks are required within the main flank and rear walls to allow sufficient ventilation for suspended floors.

Never had this done, but sounds simple for a general builder.

There is no ventilation or not enough in the roof void/loft. Most likely it requires some tile vents or a combination of ridge vents and tile vents but this would need to be properly assessed.

Just had a quote from a local roofer to do this for £300. It involves 4 vented tiles. Simple job for a roofer.

There are two chimney breasts that require external ventilation. I presume they would need vents on both ground and first floor level.

Many thanks for all help!

No idea about the last one.

I'm in St Albans, so almost London prices.

Annie1960

illusionek wrote: »

Many thanks for your answers, I will trying lowering external ground myself when I get the keys to the property.

How long before I should start seeing effects of this work? I just want to make sure that I do not wait for too long before I get professional if I screw up or if I was advised incorrectly and there is a different reason for dampness.

It may depend on the time of year, The first year I was in this house, I had a bunch of drain flies in October. I had the French drain dug out in May the following year, and I think the walls dried out over the summer. No drain flies last October.

J_B

Damp is an ongoing issue in older properties - don't get too hung up about it.
Warmth and ventilation help considerably and maybe even a dehumidifier on occasions perhaps?

illusionek wrote: »

How long before I should start seeing effects of this work?

We have a property in N Wales, the walls are 2 ft thick and when we asked our builder how long his reply was that the damp comes through at about 1 inch per month, so that was 2 years for us!!!