Damp Solutions

19/10/2024

solid stone buildings.
I have damp in my walls, should i inject them with a chemical DPC? short answer no, absolutely not. Some of you may have been talked into injecting the stone walls of your property by someone who knows no better, or is a complete and utter crook. If you know how solid stone walls are built you will understand why it simply doesn't work.
We have all seen these beautiful old stone walled properties, they look amazing '. How they are generally constructed is by building two leaves of walling, inner and outer, and in the middle of them they are filled with random loose stone or other materials. what happens over time is the loose infill will gravitate downwards leaving voids throughout. these voids can allow moisture to remain longer than elsewhere, periodically there will be a tie stone, a large stone that reaches from external wall to internal wall, thereby tying them together. they can be quite thick and perform well for years after constructed. the lime allowed them to shed excess water and vapour. it is also prudent to remember that they weren't quite as draft free as modern buildings are today which aided in the expunging of water vapours. as we enter a more modern age these properties were fitted with nice new doors and windows that were draft free and kept the place relatively warmer. then they were made more aesthetically pleasing by having cement mortars applied as pointing, or renders, and gypsum plasters applied internally. As time goes by the open fires were shut off and everything became much warmer, for a time. Now over time the salts that were released through the process of burning fossil fuels start to emerge and manifest themselves in the walling. Most of these older buildings never had a solid floor or had stone slabs as flooring or wood floors on beams etc. Anyway i digress, So now our building starts to sweat and trap moisture internally, as more moisture is trapped more salts are manifested and the cycle is perpetuated over time. You now have a seemingly unbounded problem with damp.
This is where you can fall foul of the injection people. A chemical DPC cannot have a linear path and will be invariably out of line with the internal walling too. so even if they did work on normal stretcher walling they simply cannot work here, plus the voids and the infill make it impossible to have a contiguous barrier in place.
Fixing is easy, but a lot of hard work, remove all modern coatings both internally and externally and replace with traditional coatings of lime and you're halfway there. obviously its not that simple as other factors may have to be taken into account too. roof, gutters, drainage, height of outside ground, etc etc.
Now you know, if you didn't before, that you should never inject a chemical dpc into your lovely old stone building. Each and every building is unique in-so-much-as they need to have a tailored plan of action specifically made for them to expel damp and moisture from that building. if you would like a tailored plan made for you then you can contact us and we will do our best to assist you.

11/10/2024

Almost done.

10/10/2024

Rendered Stone wall. I love stone built properties. As most of them are usually well over a hundred years old they will have been built using lime. I am not talking about modern builds that are timber construction with a dressed stone outer leaf constructed with cement mortars, but old period properties. the popular thing to do when they started showing signs of damp, especially external walls, was to render them with a portland cement render mix, some of them had fancy little swirls on them to help shed the rain or for aesthetics. Why did they do this? because they truly didnt know any better and believed what they were doing would help. we now know this is not good practice and the message is getting out more and more.
Scenario; Hi mr builder, i have damp in the walling of my 200 year old cottage, what can be done to fix it? mr builder thinks and decides if he puts a render coat on with an admixture that will prevent moisture passing through the walls to the internal leaf, also hack off that old lime plaster and put in a nice new gypsum plaster it'll look lovely and should cure the problem. And it does for many years- mostly. so mr builder applies his coating and leaves with everyone feeling happy. A few years down the line problems start to reoccur.
this scenario has played out thousands of times with each fix getting more and more aggressive. from tanking slurries to renders and repointing in cement mortars, even pitch paints and chemical liquids painted on and chemical injections, also a system using air flow through bell like objects placed in external wall to reduce damp - called holland damp system (also known as something else but i wont name it as it is a companies name i believe) to help alleviate the damp.
Firstly, what we need to realise is that buildings, of solid construction especially, need to breathe. they also need ventilating, even modern ones. cold bridging is also a factor in helping condensation reach its dew point thereby showing visibly as water droplets or slight damp which promotes mould growth and mildew-black spots, these cold spots can even allow damp to manifest inside the inner leaf or close to the surface of the internal walls as interstitial condensation. I will go through interstitial condensation more thoroughly at a later date.
Solutions I hear you ask. Well again each case will need to be examined and a plan of action put in place but lets talk about some of the solutions generically. Firstly remove any cement renders or pointing also remove any gypsum plaster internally. allow to dry out. Then replace with lime products, simple. There are lots of different lime products to use and specialists will need to apply them. Hot lime mixes are best for repointing. Insulating lime coatings help with thermal efficiency. There are some fabulous lime products for external renders which allow the building to breathe too. High ground levels need reducing, damaged drains need replacing as do guttering and down pipes. How is the roof covering, does it need repairing/replacing? Chimney stacks may need repointing or cowls put in place. Chimney breasts are another place that frequently show up as damp. this has been covered before so briefly burning fossil fuels releases salts, sulphur and soot all of which attract moisture - leave a bowl of salt on the table for a couple days and watch it get wet as if by magic - and the list goes on. Right i think i have rambled on long enough for now, if you would like help with any issue you may have, then give us a call.
I will cover timber framed buildings at a later date.

Before pictures basement.

09/10/2024

Basement flats.
if you have a basement or a basement apartment, then you will, or may soon, have encountered problems with the dreaded damp. basements are prone to damp as they are below ground level, mostly, and will, or may, have contact with the outside ground level depending on its construction. this will allow penetrating damp to enter the buildings envelope. so there it is, damp. what do we do about it? well there are as many ways to tackle this type of damp as there are conspiracy theories about the moon landings. Tanking. you will have heard about tanking, this is the process of brushing on a cementous, cement like, material onto the walls of at least two coats. this will act like a membrane and will resist the passage of moisture, for a time anyway, not recommended for extreme cases of penetrating damp. then there is a physical PVC membrane that is secured to the walls and can be rendered/plastered over, this would usually be installed with a trench/moat at the base of the walls leading to a sump with a pump operated by a float switch. alternatively this membrane system can be hidden behind stud walls and will operate as explained, access panels will need to be installed. also ventilation is extremely important.
Now if you have an older building or pre 1920 building then chances are your property will be built using lime products. If you have a basement that is damp and you have tried everything like checked drains, ventilated, etc etc. and you still have this damp then obviously further investigations are needed. after further investigations you have decided that you may need some form of tanking as you will be utilising the space, you may want to consider a lime product. Now I have talked about this system before in other posts. You could try a roman cement product, not cement that's just a term used for it, this is a lime based product used extensively across Italy in such places as Venice, yes it is a bit wet in old Venice, amongst others. this product is applied onto the walls in such a way qas the tanking slurry, obviously all voids and imperfections in the walls will need to be made good. once applied it is gently brushed over to provide a key for the next scratch coat. again there are various lime products that are used as a second/scratch coat then the final coat is applied to give a traditional lime finish to the walls. Yes it is very expensive! but it works brilliantly and is a bit of an oxymoron to say the least as it prevents excessive moisture penetrating the walls but at the same time allows them to breathe. floors can be tanked using a similar lime product, but if it is at all possible then i would recommend trying to ventilate the space first, check for external factors such as damaged drainage, leaking gutters, leaking pipework etc. also possibly consider the using land drains and french drains to divert water away from the building. if possible excavate soil away from walls and build retaining walls, and the list can go on and on as there are innumerable ways damp will enter the building. Well I hope this has given you a little insight into the complexities of damp in basements and ways of combatting it. for a definitive solution you may need to consider having a survey carried out to assess the right course of action. if you would like an assessment then contact us to arrange a viewing.

This post is just giving an insight into some causes of damp and to illustrate just how difficult it is to diagnose the problem. be wary of the little men brandishing their little two pronged diviners whilst inhaling through there teeth, exclaiming that this is going to need injecting with this and that or other. Be wary.

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09/10/2024

Finlock or concrete guttering. Finlock guttering is a terrible design as it creates a massive cold spot around the internal side of the building at eaves level. this is where condensation will prominently manifest itself and promote high levels of black mould growth. as these rooms are generally bedrooms it can have a deleterious affect on your health, particularly the elderly and young. how can you combat this type of problem? well initially you will need to ensure adequate ventilation. then you will need to ensure doors are kept shut to reduce the flow of warm moist air accessing the rooms. you may also want to purchase a dehumidifier for each room. Open windows when you can will also help. when cooking or bathing ensure you have windows open in the respective rooms to allow dispersal of moist air and install extractor fans.
Finlock gutters are prone to leakages as well, this can happen through wear and tear of the linings which can be felt, tin, fibreglass or rubber. usually you will need to remove affected area and replace it. The roofing felt can also become damaged and allow water to enter to the internal walls showing as visibly wet areas, again this will need to be repaired or replaced. Birds can damage the felt as well as this type of guttering is associated with the use of concrete tiles of some sort, like double romans, which make it easy for them to enter the roof space. here you may want to install eaves combs or guards which fit under the lowest tiles to prevent birds from entering.
Removing the Finlock gutters is a better option but it is expensive, time consuming, disruptive and messy. there are two ways this can be carried out, one is to cut the gutters back to the face of the external leaf of walling and to then add a backboard to the face of cut. this will allow the placement of 25mm kingspan insulation. then a new eaves will be formed by extending the trusses and finish it off as you would a normal eaves with soffits and facias to affix the new half round plastic guttering to. ensuring there is ventilation also. the second way is to use acros to support the eaves internally and remove the gutters completely. then rebuild walling and build eaves as above. this second option is far more expensive but is a better option. Needless to say this isnt a job for the DIYer but for someone with the knowledge and skills to carry out the work safely.
If you'd like more information on this subject then you can contact us and i will do my best to assist you.

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29/09/2024

What are the causes of damp in buildings? Continued.
2. Penetrative damp.
as the term implies this is the ingress of moisture from various sources. Ground levels, if the outside ground level of your property is higher than the inside level then you will experience penetrative damp as the water contained in the ground forces itself through osmosis {Greek for push). towards the internal wall. The external ground heavily saturated in water is forcing its way through a semipermeable membrane {wall}. In other words it soaks through the wall. A bit of a tautological ramble there but you get the point.
decayed or missing pointing on external wall can allow water to seep through into internal wall. Leaking gutters are another possible way water can find its way inside. leaking pipework or waste pipes from sink, shower, bath or toilet. Also poorly maintain rooves can allow water to enter the building, as can damaged flashings on chimneys or abutments.
Parapet walling details have become popular once more in modern buildings, I think this is a bad design and is another way water can damage walls and find its way inside the property, especially if they haven't been constructed correctly. Damaged drainage, especially below ground drainage is another cause of penetrative damp.
Solutions range from maintenance or repair of walls and rooves by repointing or reroofing/roof repair. trace leaks and repair. repair gutters ensuring that seals are in place where individual lengths are connected, repair down spouts and ensure water removal is satisfactory through drainage.
where the outside is higher than the inside then this is where it can become expensive depending on levels. ideally lower the ground level in the affected areas enough to place a pavement or walkway in its place finished level should be 150mm below dpc. in some cases this is not permissible as the property is adjacent to the council pavements or other land owners. what tends to happen with council pavements when they are resurfaced etc, they can usually just build up layer upon layer of materials as it's an efficient practice that saves them money, not you, them, you just get the honour of rectifying their mistakes. if you ask the council to lower the levels outside they will simply refuse. Anyway, I digress. In this scenario you will have to cut a channel around 5 inches to 150mm below dpc. then infill with large gravel to allow air to circulate.
It may also be necessary to place a french drain to assist in the removal of water in areas with a high water table. Now French drains can be a topic for lively debate as some believe they are nothing more than water wells bringing more water towards the building, or they can allow the ground to dry to such an extent that they can cause the building to settle causing subsidence and cracking of the walls, which is why they should be placed at least a metre away from the building and have a fall sufficient to drain area effectively.
How to install a French drain. dig out a trench to a depth that is ideally below foundation or 450mm and around 300mm wide, ensure fall is constant but gradual away from building or to the side of building and discharges either into a soak away or other drainage channel, (nb you may need permission to discharge into existing drainage. place a geotextile membrane inside excavation with a shallow layer of gravel and place the perforated pipe, with perforations facing down, place additional gravel into the trench and around the pipe then fold the membrane around the pipe and gravel and back fill. You may also want to incorporate a rodding eye to assist in cleaning out pipe if ever there is a build up of silt.
Curtain Drain or Diversionary drain systems. these are placed on the upside of a sloping site around 450mm from top of ground and form a curtain to divert water and channel it around a structure. they will remove ground water and channel it to the lower side of the property, again either into soak away or channel etc.
again I must state that here I am only giving some basic information on the subject. If you have problems with damp and need help in resolving any problem you have we could take a look and offer advice. Next post we will look at Finlock gutters, concrete gutters to you and I.

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28/09/2024

What are the causes of damp in buildings?
Nearly everyone has an opinion on the causes of damp, some are correct others not so much. lets look at the most common form of damp people often discuss known colloquially as rising damp. some say it doesn't exist others that it most definitely does and 'oh by the way you need to inject a chemical dpc', (Incidentally The Public Health Act of 1875 made it compulsory that all future buildings had to have a physical damp proof course in the walling, usually of two rows of slate, initially in London then adopted across the country.). Well lets look at this in a little more detail shall we.
if you own an older property you will have, at some point, noticed that you have wetting at the lower part of the walls. what causes this particular type of damp, I hear you say. Well, in short many things. Lets get into this. 1. Condensation, yes that's right condensation. for clarity we are talking ground floors here but this can be true elsewhere. whether you have a timber floor or a concrete floor. Causes; cold rooms, unoccupied rooms or buildings. What happens is the moist air will condense once it comes into contact with a cold surface, just look at your windows in the morning. The lower parts of walling are colder than the uppermost part of the wall and this will allow water vapour to manifest itself visibly. water vapour is everywhere in buildings, we each produce around one litre per person per day through breathing. then we have cooking, washing, bathing, the landlords nemesis - the drying of clothes inside on radiators, and not forgetting making the builders favourite liquid to ingurgitate - tea with milk and two sugars, cheers. we are just scratching the surface here but for now lets address the condensation issue. How to remedy this. Most importantly you have to have ventilation. Yes ventilation and air flow will help alleviate most of this type of damp manifestation in conjunction with other measures. trickle vents on windows will allow warm moist air to escape. exhaust fans, air bricks below timber floors will allow through ventilation of the void beneath timber floors. keeping the property heated to around 15 degrees centigrade will help in preventing cold spots to establish themselves. Ensuring there is no bridging of the plaster around the dpc will help too, you'll have to remove skirting boards to do this. this is especially true for concrete/solid floors.
In chimney breasts ensure the chimney is ventilated and has air flow throughout. chimney's can also be a great, visually speaking, area for damp to propagate. As we now prefer to heat our homes with radiators etc, we no longer use the fireplace as it was intended to be used. through the years it has been used to burn coals and wood etc to heat the home. then one day it was blocked off and retired from daily use. the burning of solid materials not only produced soot, which loves moist air, but also salts - no not your table salt trust me you wouldn.t want this on your fish and chips, anyway, these salts and sulphurs etc, are highly hygroscopic and water vapour will continue to be attracted to them indefinitely (this is also true for walls that have experienced damp in some form or other). They will migrate into the materials used to construct the chimney acting like a giant sponge. once this has happened you will need to remove the plaster/lime from the walling back to brick as we say in the trade. and remove as much of the salts as possible, there are materials you can purchase to assist in doing this too. Now I'm a great believer in lime I prefer to use lime and will promote lime in older buildings. so replaster in lime, this will allow any moisture to escape and ev***rate out of the walls. I do not like to replaster using gypsum in older buildings. In some cases i will promote a roman cement 'cement', i hear you say. No not cement but a lime product used in Venice and other Italian cities to great effect and imported from Italy, to essentially tank the wall prior to plastering, whilst allowing the wall to breath I know a bit of an oxymoron but it really does.
Still on the topic of condensation we have interstitial condensation. Interstitial condensation can remain invisible for years and will slowly over time reveal itself on the surfaces of walls. what is interstitial condensation, I hear you plead with bewilderment. to understand that you need to remember that water has three states; gas, liquid and solid. In its gaseous state, v***r, it moves around the air and through building materials. as it travels through your walls it will at some point come into an area that is cold enough for for it to morph, condense, into its liquid state, water. this is where it can start to become problematic. In solid walls the closer it condenses on the internal part of the wall the more obvious it will become and can lead to salt build up, exacerbating the problem. this can also happen in cavity walls too. A wet or damp wall will be colder than a dry wall, thus once the cycle begins it will only get worse until rectified. Again ventilation is key to prevention. It may be necessary to remove the wall coatings and reapply after.
Of course this is just a basic introduction to causes and remedies of dampness in buildings and only one scenario out of many. there are other possible ways damp can become evident such as penetrative and damp through poor maintenance or leaks from gutters, pipes, roofing and pointing. all of which i will try to give some insight in other posts. but for now if you would like assistance in evaluating the cause of damp in your property then contact us and we will advise and formulate a plan of action as best we can.
we will be updating our page shortly adding pictures of previous works and possibly uploading videos. Plus we will be continuing to expound on the topic of damp, causes and remedies.

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14/02/2024

With many years of experience in tackling damp and its causes, of which there are many, we can identify and offer solutions to rectify the root case of the particular problem that has affected your property.
Damp can manifest itself in many ways;
Rising damp, there are some that will argue the fact that rising damp simply doesn't exist and others that are adamant that it's the main cause of damp in buildings. I think both have some merit, after all why install a dpc at ffl if damp will not rise above ground level.
Generally I would say damp will manifest itself as penetrative damp in some form or other. We do not recommend chemical injection as we believe they do not work as well as advertised.
When it comes to period properties we have solutions for tackling damp in a way that is sympathetic to the structure using lime products that work exceptionally well. Some of the materials we source for serious cases of damp are imported from Italy where they are used in places such as Venice.
We are based in North Yorkshire but we can cover most of uk. Call us, or text, for a survey, not RICS, and we will do our utmost to provide solutions to alleviate damp in your property.
Please share with family and friends who may be having issues with damp. Regards Francis.

A Building company that understands damp, its causes and solutions that will alleviate the problem.