DIY - Damp proof course using cream?

trickys77

Hi All,

I'm currently renovating a property that has rising damp. I am looking to get a cream based damp proof course injected into the wall. I have been looking at this product here for example.

http://www.treatdamp.co.uk/reading/dryzone-datasheet-en.pdf

I have already removed all the plaster and skirting boards internally, so it seems like this is just a case of following the instructions by drilling and filling the right places.

Since the quotes I've had so far are around the £2000 mark, would it be feasible for me to do this? I guess the biggest question is around insurance. Since I plan to sell once refurbished the prospective buyers will be looking for a policy to cover the work. Anyone know how I would get that?

Also I realise that if a non trained person wishes to insert a damp proof course then building regs need to be advised and to inspect, but this is not an issue since they are already required for other work I am undertaking.

Any advice or recommendations would be greatly appreciated.

Thanks,

R

bryanb

Many damp treatment companies employ cowboys, you should be able to do a decent job if you research first and follow the instructions.

dougk_2

Indeed its questionable as to whether or not rising damp actually exists.
http://www.askjeff.co.uk/rising_damp.html

trickys77

Thanks both for the fast repsonses and a interesting article doug. I could see how 'moisture meters' could be misused!

My house definitely has rising damp however, since the walls are visabily wet, the joist underneath are wet to touch, the carpets were all wet, the plaster board was flaking, bowed and wet with salt lines visable. The wallpaper was also falling off at the bottom. The moisture readings in my wall are also off the scale at the bottom of the wall and they get dryer towards the top.

Does anyone know if it's possible to get the work insured if I DIY?

dougk_2

I'm not convinced its rising damp.... more like pentrating damp or water from outside at ground level coming in. The cream or injection won't solve this - only outside drainage would or a proper outside barrier (tanking)
would stop that happening in my view,

Also make sure there is plenty of underfloor ventilation as well if the joists are damp/wet. Air needs to circulate.

trickys77

Interesting, thanks again. Whats the best way to find out if it's penetrating or rising (or both!)?

My house is a 1920's so doesn't have a dpc, is of solid wall construction with render/pebble dash on the external walls. All the external paint work over the pebble dash seems to be in good condition.

dougk_2

Ideally the ground level outside should be lower than that of the floor joists inside (so a step up into the house) and the oustside ground should slope away from the house. You could install channel drainage around the house to help if this is not the case (if possible) like ACO channel drainage.
I have always made sure concrete never butts up directly to the house and used a graval channel a good 6 to 12 inches deep to help water soak away - know this isn't possibl;e if the house fronts directly onto a street.

Has the pebbledash got any cracks in it where water could penetrate and get behind?

If you lift some floorboards (assuming wooden floor) is it wet underneath? Is there a cellar is this wet and damp?

Damp comes from an external source - something leaking or the outside ground level or pentration through the walls - or it comes from condensation inside the house - warm wet air against a cold surface. Keep the house well ventilated and warm to avoid condenstaion.

trickys77

Ok thanks, I have some floor boards up so will check the moisture at various levels below them. It might be worth adding that the internal walls are all also affected (so I guess those ones must be rising damp?) I did check the ventilation and there are plenty of large air bricks all the way around the house.

No cracks that I can see in the pebbledash although it is painted which might hide small cracks underneath.

No basement.

The drive does slope slighty towards the house, but when it rain heavily water doesn't seem to collect around the base of the house. This is mainly because the roof overhangs the walls by around 500mm creating a dryish area around the base of the house.

dougk_2

If the internal walls get wet / damp that points more towards condensation I would have thought.

trickys77

Ok so I took some more readings and the walls under the floor are also wet (off the scale on the moisture meter). This continues up to a high of around 1 meter on all the affected walls. Above this height the walls have a nominal reading. The internal structural wall is also affected but the 1 stud wall I have down stairs is unaffected.

Thanks for the help, but now I'm really confused about what to do! Any tips?

David_Aldred

Hi Trickys77,
Your first question as to whether you can put a cream paste dpc in yourself - the answer is yes they are a piece of cake to do yourself. Second point if you're not sure how to do it - telephone one of the manufacturers and they will send one of their sales reps to attend site and show you how to do it and may even lend / rent you the application equipment. If you do it under their wing and have them inspect they may and it is a may issue a product guarantee on the chemicals used but all this is doing is confirming the product is fit for purpose.

Some of the leading manufacturer's are:

Safeguard Chemicals - Redkiln Close , Redkiln Way, Horsham, Sussex, RH13 5QL (tel 01403 210204) www.safeguardeurope.com

Wykamol Group – Unit 3, Boran Court, Network 65 Business Park, Hapton, Burnley, Lancashire BB11 5TH (tel 0845 4006666)
www.wykamol.com

Sovereign Chemicals – Park Road, Barrow-In-Furness, Cumbria. LA14 4QU ( tel 01229 870800 ) www.sovereignchemicals.com

You can get an approved contractor to do 'inject only' for a minimal cost and you re-plaster. The design function of that plaster has to be to hold back salts within the wall and any residual dampness. This plastering and substrate preperation requires a very high standard of workmanship that many plasterers fail to adhere to. I wouldn't advise splitting liability like this at all because if there is a problem later guess who they will blame - correct you will come out worst.

Injecting a dpc does not have to involve the Building Control Officer (BCO) but nice for them to look at whilst they are on site.

DPC work to or adjacent to a party wall requires compliance with the Party Wall Act.

Whoever installs a chemical dpc should comply fully with BS6576.

If the house was built with a dpc then it is highly likely that that dpc remains effective. A sheet membrane dpc such as bitumen is far more effective than a chemical dpc due to inherent limitations of chemical dpc's.

There is no way on god's earth you will inject a chemical dpc all the way through a chimney breast with the fireback and infill in place and especially so where they are back to back on a party wall.

A wet sub floor void / wet joist ends and dampness at low level in no way confirms dpc failure. If the house was built with a dpc then try looking at what the relative humidity within the sub floor void is.

If it is a saturated environemnt then the brickwork above the dpc will absorb that airborne moisture to be in balance with it whether or not the dpc is effective.

The same will apply to low level plaster and timbers they all want to be in balance with that high humidity.

Look whether there is debris in the base of the cavity wall sufficient to bridge the dpc and give all the effects of rising dampness whether or not the dpc is effective.

Such debris will also promote condensation within the wall and provide a pathway for penetrating dampness.

Is there a pathway for moisture that occurs within the cavity wall to vent externally before it can migrate internally?

Is there hard dense cement render and cement mortar externally compared with porous clay brickwork / lime mortar and porous plaster internally?

Is the plaster contaminated making it excessively hygroscopic?

Look at any solid floor / wall joints - is there a gap between the wall and floor where dampness can emerge whether or not the dpc in the wall is effective?

If you do not lower the moisture content in the ground floor timbers / skirting / base of door casings / base of stairs to under the threshold of decay then rot will be inevitable.

A conductivity (electrical) damp meter cannot prove rising damp - put your finger over the ends of the terminals - oops you have a reading - you must have rising damp in your fingers - er no yet the public are talked into spending thousands and thousands of pounds each year on the back of such readings.

Phrases from contractors such as 'indicative of rising damp' or 'of a pattern associated with rising damp' are used within their reports when as indicated above what they should be saying is resolve "xyz" first then monitor for drying down. If the situation doesn't resolve then laboratory analysis of the dpc may then be justified but this doesn't sell many chemical dpc's so rising damp is misdiagnosed time and again by those selling damp proof courses.

Hope this helps, kindest regards David Aldred independent damp and timber surveyor.