III Horizontal Barriers against rising damp in mansonry - Koster

HORIZONTAL BARRIERSAGAINST RISING DAMP IN MASONRYPATENTED SYSTEMPressureless; Druckinjektion; tested up DFG to 95% ≤ moisture 95 %R

Why is rising damp a concern for building owners?Rising damp is among the most frequentlyencountered causes of damage to masonrywalls. The results are usually clearly identifiablethrough spalling of plaster, damaged joints andbricks but also through salt efflorescence andalgae growth.Change of colour, reduction of the thermal insulation.Damaged plaster / renderDestruction of render and mortar jointsOver time rising damp in combination withsalt contamination and / or frost can destroymasonry structurally. Taking into account theDevelopment of mould and damage to the fabric of thestructuredecrease of the remaining lifespans of suchbuildings, rising damp causes high financialdamage every year.How does rising damp damage masonry?In masonry that is affected by rising damp,moisture is continuously transported upwardthrough the capillaries. The water evaporateson the surface and more moisture follows. Thisprocess will usually lead to an increase in theconcentration of salts on the surface. Mostevaporation takes place in the area betweenthe dry (top) and the damp part of the wall(bottom). In these areas, there are often the firstsigns of damage.

Destruction of render and mortar jointsSalt crystallizationRising dampWhere does the water come from?OutsideRain waterInsideCondensationTop ground surfaceSplash waterGround moistureCapillary condensationSeepageGround waterThere are many sources from which water canget to a wall such as rain water, ground waterand condensate (see graphic). Also leaking guttersor drainage pipes can be sources of water. Ifthe water which is entering a wall is constantlyreplenished then a continuous transport ofwater through the capillaries of the buildingmaterial will take place. The water rises upwardsagainst gravity due to a mechanism calledcapillary action.Horizontal Barriers 2 | 3

Is it rising damp?A wall with damage apparently attributableto rising damp should always be analyzed bya specialist before any renovation measuresare undertaken. Determining the cause of thedamage is always important. Information suchas the type of damage, the characteristics ofthe building, as well as the salt and moisturecontents of the building materials all have to betaken into consideration when determining howto repair the damage and remove its cause.The source of damage may not always be risingdamp. Other possibilites are: splash water abovea functioning horizontal barrier, hygroscopicaction or just leaking pipe installations. If it isrising damp, the restoration has to take intoaccount the salt and moisture content of thebuilding material. Therefore, a salt and moistureanalysis is recommended.Why does moisture rise in masonry?Interfacial tension of liquids (adhesion)Surface tension of water (cohesion)Rising damp is an effect created by the surface tension of a liquid (cohesion) and the interfacialtension (adhesion) between the liquid and the solid surface. Generally a liquid has the tendency tospread when it comes in contact with a surface. On the other hand liquids like water have a surfacetension. These two forces together, lead to the effect that water rises in a narrow pipe (see graphic).Example for rising dampBuilding materials like bricks absorb water in asimilar way to a sponge (see photo). This occursbecause masonry as well as concrete containsmall pores. Depending on the diameter ofthe pores, they can tranport water upwardsagainst gravity (rising damp). Pores with aradius between 10 -7 m and 10 -4 m show the mostdistinctive water transport and are referred toas capillaries. Between 20 % and 50 % of thepores in the building materials concrete, brickand mortar fall into that category. Pores withRising of liquids in capillariesa radius of below 10 -7 m are called micro poresand are too small for capillary water transport,where as pores with a radius of above 10 -4 m aretoo large.The smaller the diameter of the capillary, thelarger the capillary pressure and the higher thecapillary elevation. A capillary with a diameterof 1 µm (10 -6 m) can theoretically create a suctionpressure of 1.5 bar which corresponds to a capillaryelevation of water of approximately 15 m.

What have salts got to do with rising damp?Usually, the water which is transported into andthrough a wall contains salts. These salts canhave different sources:• Salts are present in the ground. They can bedissolved in ground water or ground moistureand can then be transported with the groundwater into the wall.• Salts are present in the brick itself. Thesesalts can be dissolved by the rising damp inthe masonry.• Salts have other sources such as deicing salt,fertilizer or feces which are transported by rainwater, splash water or ground water into thewall.When the salt containing water evaporates inthe surface area of the wall, the salt remains inthe wall or on its surface, leading to an increaseof the salt concentration. The salt crystallizeson the surface or in the pores of the buildingmaterial. This process is characterized bydirected growth, an increase in volume and highstrength of the crystals. When salt crystals formin the pores of a building material over a longerperiod of time, a high crystallization pressurebuilds up. This eventually leads to a destructionof the pore. Once this process has proceeded farenough, the surface of the construction materialbecomes brittle and starts to fall off.Rising dampDamaged surfaceSalt crystals on the surfaceDestructive crystallization processFrost has a very similar effect. The ice crystalsthat form when a specific amount of liquidwater freezes have a much larger volume thanthe same amount of liquid water. If waterfreezes in the pores, the expanding ice crystalsbuild up a high pressure and can lead to thedestruction of the building material.Horizontal Barriers 4 | 5

How can rising damp be stopped?There are two fundamental ways to stoprising damp: Blocking capillary active pores orhydrophobing their surfaces. Hydrophobing thesurface of a pore means to modify the surface sothat it becomes water repellent (hydrophobic).Thus, the capillary action of that pore is stopped.Blocking a pore means to partially or totally fillthe pore in order to stop the transport of water.It is crucial to bring enough material into thepore so that the diameter of the pore is narrowedfar enough and no more capillary actioncan take place.Hydrophobing : Making the building material water repellentKÖSTER Crisin® 76 stops rising damp withthree effects: It lines the capillary with a waterrepellent film. Secondly it narrows the pore somuch that capillary action cannot take placeany more. Finally, KÖSTER Crisin® 76 can cure toform a membrane over the complete diameterof the capillary.These effects together ensure that KÖSTERCrisin® 76 works every time, irrespective of porestructure, salt or moisture content. The firstbuildings were treated more than 25 years agoNarrowing/blocking the capillary, forming an elastic filmin the capillaryand those horizontal barriers are still intactand working. KÖSTER Crisin® 76 has a very lowviscosity and is not water soluble. It penetratesdeeply into even the smallest capillaries in buildingmaterials where it stops capillary actionpermanently.Due to the hydrophobic effect of KÖSTERCrisin® 76, the drying process in the wall beginsimmediately, creating an active horizontal barrieras soon as the material has been installed.Advantages of KÖSTER Crisin® 76• suitable even in cases of high moisture contentsuntil 95 % (tested according to WTA standards)• suitable even in cases of high salt contents• suitable for most types of salts(sulfates, nitrates, chlorides)• the treated substrate does not have to be alkalinefor the material to react• no prior or subsequent drying of the wallnecessary, even in case of high moisture contents• application possible even at temperaturesbelow +5°C• can not be diluted with water / is not watersoluble• resistant against most ordinary aggressivesubstances that are encountered in masonrysuch as acids, alkalis and salts• fast reaction, immediately effective• not bio-degradable• not frost sensitive• does not cause or promote corrosion of steelreinforcements• density (0,76 g/cm 3 ); penetrates deeply eveninto the smallest capillaries of the constructionmaterial• the cured material and thus the horizontalbarrier is elastic• can be applied to perforated brick and crackedor hollow masonry without having to fill thevoids beforehand• no subsequent injection necessary, one timeinstallation, guaranteed success• patented system• easy installation, horizontal drilling• proven to be effective for more than 25 years• 10 years warranty*KÖSTER Crisin® 76 ist chemically neutral and does not cause efflorescence. It is furthermore resistant againstmost ordinary aggressive substances that are encountered in masonry like diluted acids and alkalis.* Under the condition that the material is applied by a certified applicator.

The patented KÖSTER Suction Angle System isthe result of decades of experience in combatingrising damp, involving extensive research anddevelopment by KÖSTER BAUCHEMIE AG. Thehorizontal barrier is installed solely throughutilization of capillary action which is itselfthe cause for rising damp. Thus, rising damp isstopped with the aid of its cause.The system consists of the KÖSTER Crisin® 76cartridge, the KÖSTER Capillary Rod and theKÖSTER Suction Angle.KÖSTER Crisin® 76 KÖSTER Capillary Rods KÖSTER Suction AngleThe KÖSTER Capillary Rod acts like a wick, oneend is inserted into the wall and the other endinto the KÖSTER Suction Angle. From there, theit draws the injection liquid into the wall. TheKÖSTER Capillary Rod is available in a length of45 or 90 cm.This is a crucial advantage not only wheninstalling horizontal barriers into hollow bricks,vertically perforated bricks or old and crackedmasonry, but also for all other conditions. Themethod allows easy control of the distributionof the injection material in the wall. It also givessecurity in the calculation of costs for the installationof a horizontal barrier since the amountof material needed can be easily determined.Horizontal Barriers 6 | 7

How to apply KÖSTER Crisin® 76• Remove the plaster and any loose materialscompletely from the wall.• Drill the boreholes at the required distance(see table). The length of the borehole is thethickness of the wall minus 5 cm. Cleanthe boreholes, preferably with pressurised airin order to remove the dust.• After that, the KÖSTER Capillary Rod is cutto the required length (depth of the borehole+ 7 cm) and inserted into the borehole.• Then the KÖSTER Suction Angle is installedand the supply chamber of the KÖSTER SuctionAngle is filled with water. This has the effectthat the KÖSTER Capillary Rod swells a littlebit and thereby makes good contact with thewall of the borehole. Then, the cartridge filledwith KÖSTER Crisin® 76 is set into the KÖSTERSuction Angle. KÖSTER Crisin® 76 flows into thesupply chamber of the KÖSTER Suction Anglewhere the liquid is absorbed by the KÖSTERCapillary Rod. The injection liquid is transportedthrough the KÖSTER Capillary Rod. It is onlyreleased into the wall where the KÖSTERCapillary Rod has contact with the wall of theborehole. In those places where the KÖSTERCapillary Rod does not have contact with thewall of the borehole – like cracks and voids inthe masonry - no injection liquid is releasedand thus no injection liquid is lost into cracks orvoids.KÖSTER Crisin® 76KÖSTER Suction AngleKÖSTER Capillary Rod5 cm• Once the cartridge is empty, the cartridge andthe suction angle can be removed. Both canbe reused.• After the installation of KÖSTER Crisin® 76the boreholes are closed using e.g. KÖSTERKB-Fix 5.• As an ideal combination KÖSTER RestorationPlaster is applied afterwards.The consumption depends on the thickness of the wall. With the following table the consumptioncan easily be calculated.Thickness of wall ø of bore holes boreholes per Distance between drilling Cartridge per Cartridge per meter Maximum consumptionincl. Plaster meter holes from center to borehole of capillary rodcenter (horizontal) (45 cm) (90 cm)[mm] [cm] [piece] [piece] [maximum pieces per m]up to 30,0 cmup to 40,0 cmup to 50,0 cmup to 60,0 cmup to 70,0 cmup to 80,0 cmif necessary proportionally less than one cartridge can be applied14 8 12,5 1 8 8 414 10 10 1 10 12 614 11 9 1 11 16 814 13 7,5 1 13 21 1114 15 6,5 1 15 28 14

InstallationThe following pictures show the installation of a new horizontal barrier with KÖSTER Crisin® 76 in ahistoric building.1.2.The masonry is from 1750, the existing plaster is damaged.The salt and moisture contents are high.Boreholes are drilled into the interior walls at a distance of 10cm from each other (wall thickness 45 cm) up to a depth of40 cm.3.4.The boreholes are cleaned from dust by blowing the dust outof the borehole with pressurised air.KÖSTER Capillary Rods are installed so that they protrude7 cm from the borehole.5.6.The KÖSTER Suction Angles are installed so that the KÖSTERCapillary Rods reach into the supply chamber of the KÖSTERSuction Angles.The supply chambers of the KÖSTER Suction Angles are filledwith water in order to pre-water the KÖSTER Capillary Rods.7. 8.The KÖSTER Crisin® 76 cartridges are installed.The pressureless injection of KÖSTER Crisin® 76 into themasonry starts immediately after the installation of thecartridges.Horizontal Barriers 8 | 9

How fast does KÖSTER Crisin® 76 become active?Generally, the KÖSTER Crisin® 76 cartridgesempty within 48 hours after they have beeninstalled. Now the horizontal barrier has beensuccessfully installed. Due to the hydrophobiccharacteristics of KÖSTER Crisin® 76, the reductionof rising damp starts immediatelyafter the installation. The horizontalbarrier becomes fully effective withinthe curing time of the resin which cantake up to 10 days. During thisperiod, the masonry alreadybegins to dry. The dryingtime depends mainly onthe moisture contentand the thickness ofthe walls. The moisturecontent can bedetermined by takingcore samples whichare then weighed anddried according to thekiln-dry method.Often masonry burdened by rising damp containshigh salt concentrations. Therefore, duringthe first weeks of drying after the installationof a horizontal barrier, salts may diffuse to thesurface causing salt efflorescence. This is partof the drying process. The efflorescencecan be removed mechanically (do notuse water). It is recommended to applyKÖSTER Restoration Plaster after theapplication of KÖSTER Crisin® 76thereby preventing any effectsof salt efflorescence.The perfect system: KÖSTER Crisin® 76 and KÖSTERRestoration PlasterKÖSTER restoration plasters are especiallydesigned for the restoration of masonry withhigh salt and moisture contents. When risingdamp is stopped with KÖSTER Crisin® 76, KÖSTERrestoration plasters help to dry out the wall andit absorbs remaining salts. KÖSTER restorationplasters withstand moist conditions since theydo not contain lime or gypsum. They are opento water vapour diffusion and help to create ahealthy and comfortable room climate. Theyare also not effected by high salt contents andprevent salts from diffusing to the surface. ApplyKÖSTER Polysil® TG 500 as a primer in order tostrengthen the substrate and reduce the mobilityof the salt molecules. KÖSTER restorationplasters are available in grey or white. In historicbuildings they can be used as a decorativeplaster even without painting. They are suitablefor interior and exterior use.The interior walls of these buildings were restored with KÖSTER Restoration Plaster 2 White.

KÖSTER Restoration PlasterKÖSTER Polysil® TG 500Salts crystallize in the pores of KÖSTER RestorationPlaster and can not cause damage thereby.InstallationRemove old plaster. Fill breakoutsand holes with KÖSTER RepairMortar. Spray KÖSTER Polysil ® TG500 onto the surface to blocksalts and strengthen thesubstrate.At the earliest after 30 minutesapply a plaster key to ensureoptimal bonding of KÖSTERRestoration Plaster.Apply KÖSTER RestorationPlaster onto the cured plasterkey by trowel or use theKÖSTER Variojet.After approximately 60minutes, smooth thesurface.Horizontal Barriers 10 | 11

How is a horizontal barrier installed in combinationwith negative side or positive side waterproofing?Subsequent waterproofing normally includesvarious measures such as the installation ofarea waterproofing for walls and floors and theinstallation of a horizontal barrier within themasonry. The installation of a horizontal barrieris a key element in any restoration waterproofingproject.KÖSTER NB 1 GreyWaterproofing layer withKÖSTER Deuxan®Protection layer withKÖSTER Protectionand Drainage Sheet 3-400Fillet with KÖSTERRepair MortarBreak EdgesKÖSTER Polysil® TG 500KÖSTER RestorationPlaster 2 WhiteHorizontal barrier withKÖSTER Crisin® 76Waterproofing layer withKÖSTER Deuxan® 2CGliding layerProtection layerKÖSTER Polysil® TG 500Protection layerHorizontal barrier withKÖSTER Crisin® 76Waterproofing layer withKÖSTER NB 1 Grey and / orKÖSTER KD SystemKÖSTER RestorationPlaster 2 WhiteWaterproofing layerwith KÖSTER NB 1 GreyGliding layerDrainageThe left side of the drawing shows the solutionwith positive side waterproofing. It requires thatthe ground on the outside of the basement wallis excavated and the waterproofing is installedon the outside of the wall. The advantage isthat the wall is dry after the waterproofing hasbeen installed. This solution can be implementedby using the KÖSTER Deuxan® system. In thiscase, the horizontal barrier with KÖSTER Crisin®76 is placed as low as possible. The purpose ofthe horizontal barrier here is to ensure thatmoisture can not rise from the foundation intothe masonry wall.The right side shows negative side waterproofing.It is usually the cheaper and faster possibilitybecause it is carried out from the inside.The KÖSTER KD-System together with KÖSTERNB 1 Grey is the perfect choice for such a solution.The horizontal barrier with KÖSTER Crisin®76 is placed 30 cm above ground level. Thewaterproofing layer on the inside of the wallensures that no water can penetrate into thebasement. The purpose of the horizontal barrierin this case is to ensure that moisture can notrise into the constuction members above.

Pressurised or pressureless injection?Generally, horizontal barriers can be installedwith high pressure injection or with pressurelessinjection. High pressure injection requiresthe use of injection ports or so called “packers”,which are fixed in the boreholes. With ahigh-pressure injection pump, a suited materialis then injected into the wall through thesepackers. With this method the injection materialcan be applied very fast. This advantage is offsetthough, if the masonry contains voids becausethese voids would be filled with the injectedmaterial during high-pressure injection and thusbe lost. To avoid wasting injection material invoids and cracks, the boreholes are injected witha borehole suspension in a preceding work stepin order to fill voids and cracks in the masonry.The boreholes are then drilled open again andnow the material for the horizontal barriers canbe injected. Additionally, even with very highpressure, the finest capillaries cannot be filled.Pressurised injectionPressureless injectionThe KÖSTER pressureless injection method withKÖSTER Crisin® 76 in contrast utilizes the wall’scapillary action. The remedy is injected using thesource of the problem. Advantages of injectionwithout pressure are:• The injected liquid is transported effectivelyinto the capillaries which are part of themechanism that causes rising damp. Nomaterial gets wasted in cracks or voids.• The amount of material that is injected intothe masonry is easily controlled. The pressurisedinjection does not allow such goodcontrol of the amount of injected material.• Damage of the masonry and derogation ofthe statics are avoided.Angled or horizontal placement of the boreholes?With the KÖSTER Suction Angle System, theboreholes are positioned horizontally. Theobvious advantage over diagonal drilling is thatwith horizontal positioning the length of theboreholes is considerably lower. It is also easierto calculate the required length of the boreholes(wall thickness minus 5 cm). A further problemof diagonal drilling is that the installed barrierhas different levels on the inside and on theoutside. This is due to the angle of the boreholesand is illustrated in the following graphic. Thepractical result of this can be that moisturecan still “overflow” or “underflow” the installedbarrier.TOOHIGHTOOLOWCORRECTThe horizontally positioned system in contrast has the same height level on both sides of the walland can thus be easily positioned correctly.Horizontal Barriers 12 | 13

How can KÖSTER Crisin® 76 be injected in a wall that isalready saturated with water?A pore filled with water is not like a bottlebut more like a pipe. Therefore even a highlysaturated wall can be treated with KÖSTERCrisin® 76. The water flows continuouslythrough the capillary system from bottomto top. When KÖSTER Crisin® 76 is installed,the active substances use this same transportmechanism to enter the finest capillaries. Withits hydrophobic effect, it stops the flow of waterfrom the bottom and penetrates deeply into thepore structure.KÖSTER Crisin® 76 is a water insoluble injectionmaterial and is therefore not in danger of beingdiluted with the water that is already presentin the masonry. If an injected material can bediluted, the material can fail to function properly.KÖSTER Crisin® 76 cures and develops itsfull functionality even if the wall is completelysaturated with water. KÖSTER Crisin® 76 doesnot require a prior or subsequent mechanicaldrying of the wall to become effective.KÖSTER Crisin® 76KÖSTER Crisin® 76 cannot be diluted with waterKÖSTER Crisin® 76 penetrates into the capillaries and pushesout the fluids.Why is the chemical composition of KÖSTER Crisin® 76so important with regard to salts?The stream of water that is transported as risingdamp through a porous building material oftencontains dissolved salts. Salts are chemicallyactive, therefore it is very important that thereaction of the injection material is not influencedby salts. Due to its unique combinationof active ingredients, KÖSTER Crisin® 76 remainscompletely unaffected by high salt contentsof the substrate. Due to the fact that KÖSTERCrisin® 76 is not an emulsion, the ingredients donot flocculate when they come into contact withsalts but remain fully effective.How does KÖSTER Crisin® 76 penetrate so deeply intothe structure?A liquid installed horizontal barrier mustpenetrate deeply into the capillary system of amasonry in order to function properly. For thispurpose, a very low viscous liquid is required.In order to achieve a widespread wetting ofthe capillary walls, the injected material has topossess a low surface tension. KÖSTER Crisin® 76is a resin based liquid with a very low viscosity.Due to its low surface tension it is able topenetrate deeply into the pore structure of abuilding material. Additionally, KÖSTER Crisin®76 contains special additives that promote itspenetration into the building material.

KÖSTER Product Range1 External basement waterproofing2 Internal basement waterproofing3 Horizontal barriers/Restoration of masonry4 Crack and hose injection5 Concrete protection and repair6 Sealing of expansion joints7 Bathroom and wet room waterproofing8 Mould control9 Floor coatings10 Façade protection11 Balcony and terrace waterproofing12 Roof waterproofing13 Water tank and reservoir waterproofing10127811154613293KÖSTER BAUCHEMIE AG develops, produces and supplies a comprehensive range of special constructionmaterials in the areas of waterproofing and concrete repair. Being founded in 1982 in Germany,the KÖSTER Group consists meanwhile of 24 companies which are represented in more than 45countries. It is our policy to offer construction materials of highest quality, durability and generalperformance.Horizontal Barriers 14 | 15

Service you can depend onWith our service and distribution network in manycountries world-wide we can offer youprofessional advice and technical supportimmediately and on the spot. Yourrequired waterproofing materials canbe delivered promptly and will protectyour property efficiently and lastingly.For further information, please contact:KÖSTER BAUCHEMIE AG | Dieselstraße 1–10 | D-26607 Aurich | GermanyPhone: +49 (4941) 9709-0 | Fax: +49 (4941) 9709-40 | info@koster.eu | www.koster.eu