so we will show you what the surveyor is looking for and how we can repair the damage to your property.
Damp Course Injection, Rendering and Vertical Damp Course Video
Damp Proof Courses
We drill a series of holes, 2 per brick, at the internal floor level, which should be just above the old damp course. Then we inject the damp course fluid under high pressure into these holes. The whole brick then becomes a damp proof course replacing the old 1~3mm layer.
All walls, internal and external are buried in the ground and therefore all walls are in contact with wet soil at the base of the wall. If you place tissue in a cup of water, the water rises up the dry tissue very quickly, the same happens with the walls dipped in the wet soil, but it takes a while longer for the damp to climb through the bricks and mortar.
The system used to stop the damp rising up the walls is a damp course layer set at the internal floor level. Old damp courses like slate can leak as they are installed in small pieces and not as a continuous line. Bitumen damp courses are laid in a continuous line, but they can be fitted incorrectly and they can break down after 20~30 years.
All damp courses can be by-passed. Damp can rise through the mortar and if the mortar links the bricks below the damp course to the bricks above the damp course, then the damp course can be breached. Look for mortar being placed over the damp proof material on the outside of your house. This is usually done by poorly trained builders. What you want to see is black damp proof material sticking out between the bricks and not just a thick band of porous sandy mortar linking the damp bricks to the dry bricks.
The salt reacts with the plaster products causing them to swell and crumble and eventually falling off the walls. Any new plaster applied to a salt contaminated wall will suffer the same fate.
Only a 2 part treatment will cure this damage, 1st a damp course, 2nd the contaminated walls must be rendered with waterproof materials. A decorative layer of plaster can be added when the render is dry.
Damp will soak into timber products and allow the wood to become mouldy or infested or both. A noticeable smell can be noticed with timber when it becomes damp and infected. A wood treatment will save and strengthen the timbers
The liquid method uses an injection pump at high pressure to soak the solid bricks from the inside with a chemical called Triject, that will not allow damp to rise through the brick for 30 years, guaranteed. The holes are topped up later with more damp proof liquid and sealed with plugs.
Others methods include the use of a gel paste called Tri-gel seen below. The gel is applied to the mortar. The gel is pumped into the holes using a hand pump. The chemicals will penetrate the mortar and brick surface providing a barrier to stop damp from rising.
A drainage system may be required for differing ground levels where the damp couse layer is now below ground level.
Common problems that are caused by builders are
- raising the ground level with paths or paving, which in effect causes your house to sink lower towards the ground
- linking the bricks below the damp course to the bricks above the damp course allowing damp to rise past the damp course
- and mortaring over the damp course linking the unprotected bricks above the damp course to the damp bricks below.
Call Aquarius free for a free survey:
0800 0730 415 or Walsall 01922 449891
serving the West Midlands for over 10 years
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- Damp course using high pressure injection
- Damp course using a gel injection
- Damp walls with the plaster hacked off
- Damp walls that have been sprayed with silicon
Damp Course Injection
- Damp course injection
- Penetrating damp
- Mortar blobs in the cavity
- Cavity wall insulation problems
Damp Course injection and
Cavity wall problems
- Uneven ground is corrected with a drain
- 6 inch, 150mm or 2 brick splash height
- Builders have bridged the damp course
- New extension witha bridged damp course
External damp course problems
Damp Surveys
this is what the surveyor will be looking for:
There are four main causes of damp in your home
- Rising damp ; from the ground up, soaked up by the bricks, the wood and the plaster
- Penetrating damp ; rain penetrating through the walls and breaching the cavity
- Faults; missing roof tiles, faulty guttering, leaking pipes, gaps in the brickwork etc..
- Condensation ; poor air circulation, blocked vents, gas fires, cooking etc...
this is what the surveyor will be looking for:
- New houses have cavities, the outer wall can get wet like a rain coat, leaving the inner wall dry.
- Older houses do not have a cavity, so the wet outer bricks are linked to the inner bricks
- Bricks and concrete are not water proof, they soak in and hold water like a sponge
- Most mortars are porous, allowing water to penetrate faster than water can travel through bricks
- Many houses DO NOT have cavity trays, to collect any penetrating water in the cavity
- Many houses DO NOT have weep-holes, to remove the penetrated water in the cavity
- Many walls are not chemically sealed to prevent water penetration of the outer walls
- Many houses have poor over handing protection from rain, with small inadequate eaves
- Many older houses DO NOT have a damp prevention layer set at the inner floor level
- Many cavity insulations are porous and actually help water penetrate onto the inner wall
- Many cavities have obstructions such as mortar blobs, water then splashes onto the inner wall
- A recent feature is cavity wall insulation which can allow a link from the wet to the dry walls
- Even new bricks, conforming to BS5628 can absorb up to 12% of water by weight
- Even new bricks, conforming to BS5628 can contain 2.44% of soluble salts
- Soluble salts are removed by water, leaving the bricks or mortar weakened and porous
- Micro pours in the bricks and mortar, can soak water up to 1 meter above floor level
- Micro pours the bricks and mortar, can allow penetrating water through
- Soluble salts, from the bricks and mortar are carried by the water, causing white staining
- Soot and dirt can also be carried by the water through the bricks, causing dark stains
- Many outer wall bricks and the mortar are sodden with water in the winter months
- Many houses have damp bricks and mortar up to the inner floor level, below any DPC
- This water freezes and can break the mortar and even the bricks, (like exposed pipes)
- Damp which penetrates through the inner wall, can damage the plaster
- Damaged brickwork is difficult and expensive to repair and can devalue your property
- Is there 2 bricks, 150mm or 6 inches of splash height from the outside floor the damp course level
- Drives and new paths are laid over the old path, raising the outside ground level
- A salt tide mark can indicate how far up the wall the damp and soluble salts have climbed
- Salt will damage the plaster, even if you remove the plaster, new salt will damage the new plaster
- Timber floors will be sat on wooden joists which will be set into the wall under the damp course
- The damp may have penetrated into the joist ends which will weaken them
Why is rising damp a problem?
- Unlike rain which is clean water, rising damp is dirty water out of the ground
- Soluble salts in the ground rise up the bricks and mortar with the damp
- Soluble salts attack and degrade gypsum or plaster based products
- Soluble salts attack and degrade paints
- Soluble salts can leave a noticeable white tide mark on your walls
- Soluble salts remain trapped in the bricks and mortar, even if the rising damp has been stopped.
- Plastering over a salty wall will just be damaged later
- Some builders cover the damp walls with plasterboards or cladding to hide the damp
- Damp wood can be attacked by rots and wood boring insects
- Rots can give off a musty smell in your home
- Colder damp patches will attract condensation and black mould growth
- Stronger bricks are normally used below the original damp course
- Weaker bricks above the damp course can be damaged by frost if they are damp
Any plaster products 1 meter above the damp course are at risk if the damp course fails
Any timber products below the damp course are at risk
Any timber products 1 meter above the damp course are at risk if the damp course fails
Any weaker bricks up to 1 meter above the damp course are at risk if the damp course fails
It is assumed that the damp course on a new house will be effective for 30-years, after which a new damp course will need to be inserted to prevent any soluble salts from rising past the damp course.
If soluble salts pass the damp course, it will contaminate the walls. A new damp course will need to be installed to prevent any new salt from rising and the contaminated walls will need to be covered with a waterproof render.
A new damp course can save you the time and expense of hacking the contaminated plaster off and re-plastering using waterproof rendering and then plastering.
Damp Course Pricing
We have a very clear pricing policy so you can
work out how much this treatment will cost.
Damp Course Injection £15 per linear meter
Damp course inject only at ground level
Damp Proof Treatment £60 per square meter
A 1 meter wide area up to 1 meter off the ground
| Damp course | £15 |
| Remove contaminated plaster | £10 |
| Waterproof rendering | £20 |
| Plastering | £15 |
Options
Skirting
How you can save money for a damp proof treatment
| 1 ** | You can remove the contaminated plaster off yourself |
| This saves you £10 per square meter | |
| So the price would be £50 per square meter not £60. | |
| You must remove any rubble responsibly | |
| Plaster and recyclable products must be separated | |
| Local tips may accept building rubble any more |
| 2 ** | And, you can plaster the cured waterproof rendering yourself |
| This saves you another £15 per square meter | |
| So the price would then be £35 per square meter not £60. |
Additional requirements
1 Vertical damp course in each corner, £15
to prevent infecting a neighbouring dry wall
2 Separating rubble into plaster, recyclable, other etc..
Local tips will probably now not accept building rubble
A skip may be required at each site at an additional cost
Normally treatments are carried out from a corner to a corner
so;
1 if the middle of a wall is damp, the treatment would include the whole wall
corner to corner.
2 if a corner is wet, 2 whole walls would be treated, corner to corner, to corner.
The price would be calculated by measuring the length of each of the walls,
corner to corner, with vertical damp courses in each of the end corners so
that the damp can’t move to a neighbouring dry wall.
Minimum Charge
It costs £300 to get a crew, van, fuel, materials, equipment etc to a site each day,
so we have a £300 per day minimum charge.
Price example 1
Normal Damp Proof Treatment ~ at £60 per square meter
the whole treatment
Day 1
Remove the contaminated plaster
Drill and insert damp course injection
Render the required area, allow to cure (dry)
Day 2
Plaster the cured or dried render
If we are
| removing contaminated plaster | £15 |
| inserting the damp course | £15 |
| waterproof rendering | £15 |
| plastering | £15 |
| TOTAL | £60 |
This would be a 2 day job and so the minimum charge would be £600.
So that this was economically viable, you need to have 10 meters of
treatment being required, 10 meters x £60 = £600.
Any less than that, say 9 meters would still cost £600.
Price example 2
Damp Course Injection & Waterproof rendering only,
the chemical treatments only.
Day 1
Drill and insert damp course injection
Render the required area, allow to cure (dry)
If we are
| inserting the damp course** | £15 |
| waterproof rendering | £15 |
| TOTAL | £30 |
This would be a 1 day job and so the minimum charge would be £300.
So that this was economically viable, you need to have 10 meters of
treatment being required, 10 meters x £30 = £300.
Any less than that, say 9 meters would still cost £300.
A maximum safe working treatment that can be completed in each day
would be 20 meters, which may extended to 25+ in larger rooms.
In most cases, the ground level bricks will need treating and the plaster will have to be replaced
- Damp can severely reduce the value of your home because of the potential future repair costs
- Once damp has started to penetrate your house, it can very difficult to stop
- Redecoration can remove the effects of the damage, but you should tackle the causes of damp
- To remove the causes of damp penetration, you need to consult a damp prevention specialist
- If you have a timber floor, the joist ends will be sat in damp bricks below the damp course.
- These joist ends will need checking. Hopefully they will only need treating.
Call Aquarius free for a free survey: 0800 0730 415 or Walsall 01922 449891
serving the West Midlands for over 10 years
see an example of our damp courses
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www. West Mids Carpentry .co.uk ~ experienced & qualified carpenter, joiner & kitchen fitter
