Penetrating Damp Problems
A) Penetrating damp is caused by block cavities when there is a lot of debris such as sand and mortar and parts of bricks and wood left over from the original build bad building practices today. This material gets wet and penetrates on to the internal wall this damp then rises up onto the internal plasterwork and looks like rising damp and which makes it look like the Dpc has failed.
B) Other courses of low level penetrating damp are heavy soils raised up and touching the property’s external walls causing this constant wetting and with blocked cavities this damp transfers across on to the inner wall and timbers.
C) These properties have climbing plants, these types of plants grow by sending their root system into the mortar which causes the bed joints to open and force out the sand and lime mortar. This will leave your wall open to driving rain and damp patches high up on the wall. And with this much foliage the wall cannot evaporate any excess moisture. Wall ties will also be exposed to the elements and will start to rust away.
D) Penetrating damp is also caused due to new raised ground levels and the Damp Proof Course (DPC) being breached also the render is touching the ground drawing moisture. The render being cement is cracking and it has been render to the ground this is causing moisture behind it and forcing it to detach from the wall. This will bypass the current DPC.
E) Remember a Dpc is a physical barrier to stop moisture traveling upwards you would be very unlucky to have one fail completely. A dpc will not stop anything, if things are going under it or over it.
F) If Rising damp is suspected in vast cases it will really be penetrating damp which transfers across a wall and not up through the Dpc.
If the DPC has been broken or removed due to building work then another can be inserted and over lapped to make a new DPC.
Defective Guttering and Downpipes
Constant wetting in the same area will allow water to soak through the walls this will be due to lack of maintenance in many cases.
Defects liked blocked or broken gutters, broken downpipes and blocked drains are some of the common faults which cause internal damp by penetration.
Blocked Air Vents and Cavity Walls
When air vents and cavities are blocked this will stop air circulating under the floor and will increase the dampness in timbers. As this moisture increases the right conditions for wood rotting fungi will increase and create the right conditions for wood boring insect.
It is quite common in old houses to have blocked cavities due to poor building practices of the time.
These large amounts of building materials are carelessly left in there because early Victorian builders didn’t fully understand the cavities purpose.
Also when older houses had there sash windows replaced with new plastic PVC the old sash weights and wood were left in the cavity causing damp to transfer to the inner wall.
Some cavities have vast amounts of material in them causing damp to penetrate onto the internal walls making it look like rising damp and a failed Dpc.
If a property has had its old sand and lime plaster replaced or has been skimmed over with pink gypsum plaster which isn’t breathable and the property suffers from high humidity. This will make the plaster damp and were this material holds a natural amount of natural salts such as nitrates, chlorides and sulphates they can be carried within the moisture.
Some of these salts are hydroscopic (attract and hold water vapour from its surroundings) and can make a wall appear to have rising damp or some kind of damp penetration, when in fact it is damp humid air in a room attracting moisture from the atmosphere.
A cement plinth with some of the render removed shows how when the plinth cracks and shrinks how it traps damp behind it at a lower level. This is made much worse by higher ground levels keeping the plinth constantly wet and now bridging the DPC this has allowed plant roots to also make the area worse by retaining more moisture.
These cement plinths where originally put there as decoration to hide the DPC. These days when they fail all they do is let water in at a lower level and not let it out this trapped damp will appear on the internal plasterwork at a lower level along the skirting board.
A French drain is simply a shallow gravel ditch excavated near the base of the wall. This helps disperse damp that would otherwise collect and soak into and up a brick wall, by allowing the moisture to evaporate away first. If the ground is considered to be too wet a perforated pipe can also be used to divert water further away from the house. This is done by digging an extended trench into the garden, before back filling with 20mm – 40mm gravel.
One of the most common damp problems is caused by defective plumbing these leaks can go unnoticed for months or years causing serious damage to sub floor areas. Copper pipes can develop miniscule holes caused by corrosion and this is a particular problem with unprotected copper pipes laid in concrete floors.
Older houses are affected by this problem more every year, soft sand and lime mortars are washed away by weathering and allowing rain penetration.
As well as preventing rain penetration and protecting wall ties from corrosion good pointing makes the house look better again.
Building Cracks in External/Internal Brickwork
All buildings move and most will show some signs of cracking at some stage, many cracks have been there for decades such as historic structural movement which has now stabilised and mean very little. Sometimes these cracks are danger signs such expanding corroding wall ties but mostly it’s just your house adjusting to the seasonal weather changes during the year.
Any minor cracking may simply be your old house shuffling about on very shallow foundations like it always has and with general maintenance these cracks can be refilled. Always call for advice if you have any concerns about these problems.
Houses which suffer from this problem are caused when the old sand and lime mortar has been eroded away with time as it was supposed to, this protected the soft handmade bricks and aloud the mortar to expel moisture. Spalling is caused when the old sand and lime mortar is replaced with much harder sand and cement which is tougher than the old bricks and doesn’t allow moisture to be expelled through the mortar bed.
What happens now is that that trapped moisture cannot pass through this harder mortar and forces it way out through the face of the brick causing it to blow the face of the brick.
Woodworm Infestations Treatment
Most of our woodworm treatment takes place in the lofts of houses as that is where most seem to start because these little beetles fly into them and start there life cycle. But any long term woodworm infestation in a house with softwood such as pine in its construction can and does seem to spread. They do like the ground floor area this probably due to sub floor timbers attracting slightly more moisture and making the wood more easily attacked.
They will spread along the floor joist and underneath the floorboards into other rooms in the sub floor areas and when the grubs are ready emerge from there flight holes as adult beetles. The woodworm treatment we off will quickly stop the infestation and the woodworm life cycle as the product soaks into the wood.
The woodworm treatments we offer can easily stop the wood boring insect infestation which is alive in your house and causing damage to your construction timbers. A woodworm treatment is applied to prevent the further damage caused by the woodworm grub
Active Beetle infestations like the common furniture beetle are common today because much of the timber used in construction is softwoods such a pine. Everything in your home from the roof joists to the floorboards is made from it and they like to infest damp timber.
Properties from the 16th, 17th and 18th Century tend to have much more hard wood in there construction like oak and suffer attack from the Deathwatch beetle in damp conditions.
Common Furniture Beetle
The common furniture beetle is the everyday name given to the insect which de Geer called Anobium punctatum in 1774. The common furniture beetle belongs to the family ANOBIIDAE which contains about twenty two different species found in Britain.
The adult beetle varies in size from 2.5 mm to nearly 4.5 mm in length and is usually chocolate brown in colour. All are covered with fine yellowish down which does not however hide the longitudinal rows of punctures or small pits on the elytra or wing cases.
The Deathwatch beetle is an indigenous British insect which due to its habits has been well known for several hundred years. It was given the name Xestbbium rufovillosum by De Geer in 1774 which is the name now commonly used although in older text the name tessellatum was used
The Death Watch Beetle is a wood boring beetle, typically sized between 6mm - 9mm, the females slightly larger than the males and larvae growing up to 11mm long. It is dark greyish brown in colour with a pattern of yellowish scale like hairs on the pronotum and wing cases. The wing cases however often become rubbed when the colour may be more reddish and shining. The longitudinal rows of small pits on the wing cases, present in Anobium punctatum are absent in Deathwatch.
Because old cob cottages were built on stone plinths, the effects of rising damp should never become a problem as long as there is adequate external land drainage. Specific attention should be paid to the build-up of soil that surrounds the stone plinth. As overtime this can build up leading to water penetration.
Wall tie failure
In old Victorian and Edwardian homes early wall ties were large fish tail items made from galvanized steel because this was the best product of its time. But there was an understanding that due to the material used that sometime in the future they would probably have to be replaced due to corrosion.
When these large wall ties do start to corrode seriously, they expand under the bricks and can cause horizontal and vertical cracking.
Raised Ground Levels
Many properties over time have had the ground around them raised to install new paths and driveways this has had a negative impact on the house its self.
In some cases it has blocked air bricks and in others it has gone above the properties Dpc which prevents rising damp affecting you and your internal timbers. In others if you have a rendered property it will allow moisture to travel up the render and pass your Dpc and cause penetrating damp.
Damp Proofing and Woodworm Treatment Surveys
Once you have a fault and it takes affect long term then damp problems start to appear they manifest themselves into one of several common types of damp; rising damp, penetrating damp, salt damage or condensation due to excessive internal humidity.
Any one of these damp issues can then lead to secondary problems such as wet and stained walls, woodworm infestation, wet and dry rot outbreaks and wall tie replacement due to corrosion or spalling brickwork.
You may need a professional damp, woodworm, waterproofing or building survey report because you are buying or selling a property. Or have had a Home buyers report and need questions answered fast and reports within 48hours.
Free Sales Quotations for Property Faults
A sale quote allows a prospective buyer of our services to see what costs would be involved for the work they would like to have done without the need for a detailed survey report.
Don’t be damp Be Dri call us today and let us help you with any of your damp proofing, woodworm treatments, wall tie replacement, repointing brickwork and wet and dry rot issues.
It’s free to call and costs nothing to ask your questions.