A METHOD FOR PROVIDING A PERMANENT MOISTURE SEAL

Abstract: On providing a durable moisture barrier on concrete surfaces and the like the superficial layer is first dried deeply under forced blowing on of a drying medium having a low relative humidity, preferably hot compressed air, whereupon a deep impregnation agent, having the ability to react with moisture and components of the concrete to form a sealing gel, is added and is permitted to be absorbed by the superficial layer and to react therein. The just mentioned steps, if desired preceded by a water soaking, may be repeated close to each other, unto there is no noticeable tendency to absorption of the impregnation agent.

Description: A METHOD FOR PROVIDING A PERMANENT MOISTURE SEAL The present invention relates to a method for providing a durable moisture seal within a body of concrete or the like by means of a deep impregnation agent, particularly within the superficial layer of a concrete body, such as a flooring, a wall or the like, possibly having a surface smoothing base, e.g. a self leveling so called float putty. The invention will be discussed below with reference par¬ ticularly to problems with floor and ground constructions but the invention is by no means restricted to that fiel3 only, as it is generally applicable to all those cases where moisture penetration or permeation and problems inherent therewith may be present or may arise. Prior to disclosing the invention in detail it may be worth while to discuss the general problems of the building industry in these connections, and the common methods to overcome such problems as far as possible. It is a general problem within the building industry that in many cases, where self leveling so called float putty has been used before carpeting, a bad odour arises as soon as moisture occurs. The moisture may come from building moisture, i.e. moisture within and on the building material, which one, due to time pressure during the building job, has not afforded onself time enough to remove, or which one has simply "built in", because the building job has proceeded so fast that time has not permitted the old time months long or even half year long drying of the building. The moisture may also depend on steam evaporation from ground bound water, particularly in connection with modern low house build¬ ings. Of course, a very frequent source to moisture penetration into buildings is various leakages, floods etc. Modern floor and ground constructions are very susceptible to so called cold bridges, due to a high RH-value (relative humidity) . Often there arises a capillary condensation with both a capillary pressure and an attendant steam pressure. Due to that, there arises between the float putty surface and the co¬ vering, being e.g. a plastic mat or a protective plastics beneath for instance parquet, a very strong alkalic moisture layer, which constitutes a strongly active solvent. This chemical solvent is indeed so strong that for instance protec¬ tive plastics of older qualities do not withstand attacks therefrom, for which reason discolouring of parquet is a common problem. To remedy the above mentioned problems and other problems which are due to moisture penetration or moisture permeation a number of different methods have been proposed. E.g. surface coated chemical moisture barriers of a duffusion tight type and having a specially strong adherance have been proposed» Of course, such moisture barriers pre¬ suppose that there are no capillary forces beneath, which might disturbe the adherance. In certain cases one has tried to use mats and tiles of a diffusion open, character which, however, require very careful investigations. This is because it is important to establish that the moisture addition from below does not exceed the permeability of the cover. Normally, such investi¬ gations are so time and money demanding that the result does not justify the efforts. Beyond the above methods also various chemical moisture barriers have been proposed, viz. the whole range from super¬ ficial coatings, which penetrate into the concrete or base, to deep impregnation. The last mentioned type of a chemical moisture barrier has been used in USA since the 1920:ths, and forms a part of the concrete. Particularly if a superficial coating of a diffusion tight character should be applied after the impregnation a problem arises, viz. that the impregnation agent requires some prerequisites for the application thereof, such as a certain minimum temperature and a hydrophilic or at least not hydrophobic base character of the concrete/putty base. Up to now, these inevitable requirements have very considerably restricted the possibility to an efficient and rational use of the deepi pregnation agent in question. Further, it has been established that it is close to impossible to introduce an impregnation agent into a water saturated pore system. Both the varying temperature and the varying character of the concrete/putty base with respect to its hydrophilic status make that the time required for a satisfying preparation may vary from some hours up to weeks or months. Of course, such a condition is entirely unsatisfying for a rational work. Further, the described condition constitutes an extremel great drawback with respect to the possibility to calculate the total costs for carrying out a rehabilitation or to. provide for a durable moisture barrier already at the building stage in as much as the additional costs for moving the personnel, costs for rent of alternative facilities etc often result in higher costs than those for the performance of the actual job. The present invention aims at providing a method for the provision of a durable moisture barrier by means of a deep impregnation agent, on the application of which the above mentioned drawbacks are obviated at the same time as the efficiency of the impregnation is improved. To the just mentioned end it is proposed according to the present invention a) that the superficial layer should be dried under a forced blowing on of a drying medium having a low relative humidity and a low partial vapour pressure, preferably hot compressed air, and under an optimal control of at least two of the following parameters which are essential to the drying result, viz. 1) the difference in partial vapour pressure between the drying medium and the layer immediately above the surface to be dried (saturation vapour pressure) , 2) the velocity of the drying medium and 3) the evaporation, b) that a liquid deep impregnation medium, having constituents possessing the ability to react with moisture and components of the concrete to form a sealing gel, is added and permitted to be absorbed by the material under impregnation, and to react therein, and c) that the steps a) and b) are repeated, if necessary, preferably close to each other, until there is no longer a noticable tendency to absorption of the impregnation medium. According to the invention an impregnation medium is preferably used which has a high penetration ability and has the ability to form such a sealing gel that after the impreg¬ nation the difference in vapour pressure between the mouth of existing capillaries and deeper portions thereof is so small that the diffusion, depending on the vapour pressure difference, becomes neglectable or is set to a predetermined value. According to the invention it is further advantageous, in certain cases, to use in a separate step, or, alternatively, in at least one of the deep impregnation steps, a medium which contains constituents which will kill sponges and/or mould fungi. As the deep impregnation medium rquires at least some moisture to be able to form the sealing gel it may be found feasible, in some cases, as a preparatory step to the above mentioned drying step a) to soak the surface under preparation with water and permit the water to penetrate into the concrete to the required quantity and the required depth so that at least the moisture quantity required to form the gel should remain also after the drying step a) .

Claims: Claims 1. A method for providing a durable moisture seal within a body of concrete or the like by means of a deep i prenation agent, particularly within the superficial layer of a concrete body, such as a flooring, a wall or the like, possibly having a surface smoothing base, e.g. a self leveling so called ■ • float putty, characterized by the combination of the following steps: a) the superficial layer is dried under a forced blowing on of a drying medium having a low relative humidity and a low partial vapour pressure, preferably hot compressed air, and under an optimal control of at least two of the following parameters that are essential to the drying result, viz. 1) the difference in partial vapour pressure between the drying medium and the layer immediately above the surface to be dried (saturation vapour pressure) , 2) the velocity of the drying medium and 3) the evaporation, b) a liquid deep impregnation medium, having constitu¬ ents possessing the ability to react with moisture and compo¬ nents of the concrete to form a sealing gel, is added and permitted to be absorbed by the material under impregnation and to react therein, and c) the steps a) and b) are repeated, if necessary, preferably close to each other, until there is no longer a noticable tendency to absorption of the impregnation medium. 2. A method as claimed in claim 1, characterized in that an impregnation medium is used which has a high penetration ability and has the ability to form such a sealing gel that after the impregnation the difference in vapour pressure between the mouth of existing capillaries and deeper portions thereof is so small that the diffusion, depending on the vapour pressure difference, becomes neglectable or is set to a predetermined value. 3. A method as claimed in claim 1 or claim 2, charac¬ terized in that there, in a separate step, or, alternatively, in at least one of the deep impregnation steps, is used a medium which contains constituents which will kill sponges and/or mould fungi. 4. A modification of the method as claimed in one of claims 1 - 3, characterized in that, as a preparatory step to the drying step a) , the surface under preparation is soaked with water, and the water is permitted to penetrate into the concrete to the required quantity and the required depth so that at least the moisture quantity required to form the gel remains also after the drying step a) .

Inventors: HARTZELL GOERAN, SKOGSBERG CHRISTER, HARTZELL, GOERAN, SKOGSBERG, CHRISTER
Applicants: EVER SEAL SYSTEMS AB
Application year: 1988
Main classification: E04B1
IPC codes: E04B1