A membrane is a selective barrier; it allows some things to pass through but stops others. Such things may be molecules, ions, or other small particles. Biological membranes include cell membranes (outer coverings of cells or organelles that allow passage of certain constituents); nuclear membranes, which cover a cell nucleus; and tissue membranes, such as mucosae and serosae. Synthetic membranes are made by humans for use in laboratories and industry (such as chemical plants).
This concept of a membrane has been known since the eighteenth century but was used little outside of the laboratory until the end of World War II. Drinking water supplies in Europe had been compromised by the war and membrane filters were used to test for water safety. However, due to the lack of reliability, slow operation, reduced selectivity and elevated costs, membranes were not widely exploited. The first use of membranes on a large scale was with micro-filtration and ultra-filtration technologies. Since the 1980s, these separation processes, along with electrodialysis, are employed in large plants and, today, several experienced companies serve the market.The degree of selectivity of a membrane depends on the membrane pore size. Depending on the pore size, they can be classified as microfiltration (MF), ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (RO) membranes. Membranes can also be of various thickness, with homogeneous or heterogeneous structure. Membranes can be neutral or charged, and particle transport can be active or passive. The latter can be facilitated by pressure, concentration, chemical or electrical gradients of the membrane process. Membranes can be generally classified into synthetic membranes and biological membranes.

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  1. M

    Extension floor - decoupling membrane?

    Hi, I had a small kitchen extension built a couple of years ago. The new sand and cement screed has been taken right up to the old one over where the old external wall used to be. Obviously after a couple of years this has now well dried out. The new floor has more insulation than the old. The...
  2. djkprojects

    Joining Ditra membrane and Jackoboard

    Hello guys, I'm doing a wetroom and will be using Ditra Heat Duo membrane for the UFH. I looked at Kerdi Boards for walls and Kerdi LTS for the shower tray but these are double the price of for example Jackboard so I thought of using that on walls and shower tray instead but my question is how...
  3. djkprojects

    Ditra membrane + adhesive

    Hello, Hopefully someone can advise as I'm confused when it comes to choosing correct adhesive when working with tiles or decoupling membrane. 1. I'm doing a wetroom with plywood subfloor + ditra UFH membrane What adhesive do I need to adhere the matting to the plywood? I've looked at Ardex...
  4. T

    Preparation Damp Course Membrane Distance - Critical?

    I have removed my old patio 60cm x 60cm concrete slabs which started from the back door of my house to the start of my garden, roughly 2.4 meters. The end of the patio is supported by a 2 course brick container wall running the length of the patio, about 4.4 meters. I have laid the hard core and...
  5. O

    Debonding membrane needed?

    Hi all, I’ve got an outdoor patio that has a concrete slab, onto which I’ll be laying 20mm porcelain (900x600) tiles. I was wondering if a decoupling membrane is necessary given the thickness of the tiles - seems like it might be overkill. I see conflicting advice online. perhaps a s2 adhesive...
  6. U

    help with 6mm floor tiles

    Hi guys, newbie here and after advice/opinion So we have 210sqm of 120x120x6mm porcelain floor tiles to go down onto UFH with a Chemfloor cement floor. I have been told I need decoupling mat due to the size and been told not to use the membrane due to potential air pockets that could cause...
  7. G

    Granolithic finish over bitumen sheet membrane?

    Hi All, I have a job that requires me to cover up a pedestrian walkway in granolithic finish. However, the owner has already gotten his waterproofing contractor to install a bitumen sheet waterproofing membrane. I have read some disadvantages of tiling over bitumen, not sure if the same issues...
  8. Tillly

    6" waterproof adhesive membrane tape for niches in shower wall.

    Hi all, I am hoping to find some help. A false wall has been constructed in my bathroom and two niches have been put into it. The 'wall' has been boarded over with aquapanel cement board and the niches have been constructed with the same. I need to tile the entire bathroom now, but taking it...
  9. A

    Can i use normal set S1 adhesive to install an uncoupling membrane?

    Hi all I will be installing an uncoupling membrane on a 100sqm floor ( concrete ) Which I have now releveled But I was wondering do I have to use a rapid set or can I use normal set S1? Thanks
  10. D

    My 1st Job I have part completed shower stall with a partial Schluter kerdi membrane install on the floor. Can I pour Levelquick over the Kerdi? Then new Kerdi?

    I have part completed shower stall with a partial Schluter kerdi membrane install on the floor. Can I pour Levelquick over the Kerdi? Then new Kerdi on top? It seems the slop to the drain is too steep and I want to reduce it to 1/8" per foot. The shower is 78" by 48" if that matters
  11. C

    Setting Out Is an anti-crack membrane necessary on old concrete.

    I was wondering what the opinion is of this forum regarding laying porcelain tiles on an old concrete floor. The floor is 28 square meters being laid with porcelain tiles on a concrete floor that was poured 20 years ago, the house is a new build that was never completed. From what I’ve seen the...
  12. A

    How to use a trowel on top of a tanking membrane

    Hi everyone, I'm a DIYer with a week's training how to tile. I am about to tile my shower. I plan to use a tanking kit first such as the MAPEI one. My question however is, would the trowel scratch the surface of the cured membrane, causing a breach and negating any waterproofing done?
  13. J

    Decoupling membrane and epoxy grout in new build

    Hi I am posting in the hope that someone may be willing to offer me some advice about floor tiles in a new build property. The house has a screed floor with under-floor heating. I need to have about 100 sq metres tiled downstairs (hall, kitchen, utility, living room). The tile will be...
  14. L

    tiling directly onto damp proof membrane

    hi guys, i have some damp-proof membrane installed in my bathroom floor(Capital Valley Plastics Ltd Damp-Proof Membrane Black 1000ga 15 x 4m - Is it possible to tile directly onto this?
  15. J

    Decoupling membrane over proforma/wetroom shower tray?

    Hi All, Can someone please advice on the following..... I have a proforma shower tray (20mm) that is sitting on the joist . Butted up against the tray is 18mm ply to form the wetroom floor. Question - do I lay decoupling membrane over the shower tray and ply? or can I lay the membrane over the...
  16. K

    RedGard over membrane

    I installed a pre-sloped 32"x60" foam shower base with offset drain. The membrane material is also installed. Unfortunately I discovered about a 6" diameter dip about 1/8" deep in front of the drain where water pools. Could I fill that area with unmodified thinset and paint over with RedGard...
  17. B

    Will thick DPM sheet act as a poor mans decoupling membrane?

    Hi, I've put some latex self level on a ply overlay(all done right) and wondered if I could use some thick DPM sheet as a decoupling membrane - am totally skint and wondered if anyone has tried this or what you think please? cheers
  18. V

    Decoupling Membrane suppliers

    Hi Looking for advice for decoupling membrane. I have around 60m2 to tile with 20mm limestone tiles. Main room is 40m2 with expansion gap in mmiddle. I have put wet UFH and screeded with sand cement. Screed has been down and 10 weeks now and heating has been on full blast with no problems...
  19. C

    Advice on Tiling over a bitumen tanking membrane on an external balcony.

    Hi. I have a leaking balcony on my property it’s 3.5m x 1.25m so not large. Its a concrete floor with brickwork sides. I have put down a bitumen based tanking membrane I would like to know the best way to put tiles down on top of this. any help would be appreciated. Charlie
  20. D

    Mapei liquid membrane safe with kerdi?

    is mapei liquid membrane ok to come into contact with kerdi? Hello First time poster- embarking on a wetroom project. I wonder if you can help with this first query please ... the wall area I’m going to tile will have kerdi matting but planning to also apply mapei liquid waterproofing membrane...
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