Testing standard
Adhesives for tiles — Determination of tensile adhesion strength for cementitious adhesives
Written and technically reviewed by Dak System Inc. engineeringLast reviewed
EN 1348 is the tile adhesive pull-off test: ceramic tiles are bedded in cementitious adhesive on a standard concrete slab, conditioned under one of four regimes, and then pulled perpendicular to the slab at a constant rate of force until the bond fails. The result is a tensile adhesion strength in newtons per square millimetre, and the set of four regimes is what supports the C1 and C2 classification. EN 1348:2007 was withdrawn in February 2017 and superseded by EN 12004-2:2017, which carries the method; a specification naming EN 1348 today should name EN 12004-2 instead.
Ceramic tiles are bedded into cementitious adhesive spread on a standard concrete slab, under a defined load. The assembly is cured, then conditioned by one of several regimes. A steel pull-head is bonded square to each tile face with an adhesive stronger than the mortar, and the tile is pulled perpendicular to the slab until the bond fails. The force rises at a constant 250 newtons per second, plus or minus 50, and the failure force divided by the bonded area is the tensile adhesion strength.
Adhesion in the direction that actually pulls a tile off a wall, in newtons per square millimetre. One figure is only part of the answer, because the method is run after four histories: 28 days in standard conditions; water immersion; heat ageing at 70 °C for 14 days; and 25 freeze–thaw cycles. An adhesive strong dry and weak after immersion is the wrong adhesive for a shower whatever its dry figure says, and one that survives water but not freeze–thaw is wrong for an external terrace. The set of four is the result. Those figures underpin the classification everyone specifies by: an adhesive is C1 or C2 because named values from these named regimes cleared the limits in the requirements standard, EN 12004-1 since 2017. Reporting the standard-conditions figure alone and letting it stand for the rest is the commonest way a product is compliant on paper and not on site.
There is no specimen to machine. There is an assembly to make, and almost every source of scatter in the result is introduced while making it.
A result without its conditioning regime attached is unusable, however carefully it was measured. An adhesive strong dry and weak after immersion is the wrong adhesive for a shower whatever its dry figure says.
Failure force divided by the bonded area
Reported in newtons per square millimetre, which is numerically the same as megapascals.
One strength per conditioning regime
The regimes are the point of the method. Reporting the standard-conditions figure and letting it stand for the rest is the commonest way a product is compliant on paper and not on site.
Where the assembly came apart
Adhesive failure at the slab, at the tile, cohesive failure in the mortar, or failure of the pull-head bond. The last of those is not a result at all.
A pull-head bonded out of square peels one edge first. It gives a low result and a failure surface that looks like poor adhesion, and nothing in the force trace distinguishes it from a genuinely weak bond.
A cell sized for the bond rather than the frame. A tile of this size fails in single-digit kilonewtons, and an accuracy class applies only above a stated fraction of capacity — so a machine's largest cell is very likely outside the range its own certificate covers at this load.
SpecificationsA truly perpendicular pull at a controlled force rate, and very little else. Capacity is not the constraint: a small tile at a few newtons per square millimetre fails in single-digit kilonewtons, so a modest frame is ample and a load cell chosen for that range resolves far better than one sized for the machine. What the work demands is squareness and repeatability across many tiles on one slab, which is why a positioning arrangement reaching each tile in turn beats moving a heavy slab under a fixed head. Loading is rate-controlled in force, not displacement, so the frame has to hold 250 newtons per second steadily to failure. Conditioning is as much part of the method as the frame: immersion, heat ageing at 70 °C and freeze–thaw cycling all have to run to schedule.
A pull-head bonded out of square, peeling one edge first and giving a low result with a misleading failure surface. Bonding adhesive not fully cured, so the head releases before the mortar. Slabs drifting from the standard specification, or varying in porosity between batches, which reads as adhesive variability. Loading by displacement rate rather than force rate. And reporting a result without naming its conditioning regime, which makes the number unusable however carefully it was measured.
| EN 1348:2007 | EN 12004-2:2017 | EN 12004-1:2017 | |
|---|---|---|---|
| Status | Withdrawn, February 2017 | Current | Current |
| Carries | The tensile adhesion method alone | The test methods, this one among them | The requirements, classes and marking |
| Answers | How strong is the bond, after which history? | How is each characteristic measured? | Is the adhesive a C1 or a C2? |
| Cite it today? | No — it names a withdrawn document | Yes, for the method | Yes, for the class |
The method did not disappear when EN 1348 was withdrawn; it was carried across into EN 12004-2 with EN 1308, EN 1323, EN 1324, EN 1346, EN 12002 and EN 12003. A specification that still names EN 1348 is asking for work that can be done — under the reference that now holds it.
| EN 1348 | ASTM D4541 | |
|---|---|---|
| System | Cementitious adhesive under a ceramic tile | Protective coating on a substrate |
| Loading | Force-controlled pull normal to the surface | Pull normal to the surface with a portable tester |
| Reports | Tensile adhesion strength with a failure mode | Pull-off strength with a failure mode |
| Conditioning | Four defined regimes are part of the method | As the specification requires |
The arrangement is nearly the same and the numbers are not transferable. The bonded area, the substrate, the loading rate and the conditioning all differ, and D4541 was written around portable adhesion testers rather than a laboratory frame.
No. EN 1348:2007 was withdrawn in February 2017 and superseded by EN 12004-2:2017, Adhesives for ceramic tiles — Test methods, which absorbed it along with EN 1308, EN 1323, EN 1324, EN 1346, EN 12002 and EN 12003. The method itself was carried across rather than dropped, so the work is unchanged; only the reference has moved. A drawing or tender still citing EN 1348 should be read as calling for the tensile adhesion method now published in EN 12004-2.
The tensile adhesion strength of a cementitious tile adhesive — the force needed to pull a tile perpendicularly off a standard concrete slab, divided by the bonded area, reported in newtons per square millimetre. That is adhesion in the direction that actually pulls a tile off a wall, which is why it is the figure the classification system is built on.
Because the method is run after four different histories: standard conditions to 28 days, water immersion, heat ageing at 70 °C for 14 days, and 25 freeze-thaw cycles. An adhesive that is strong dry and weak after immersion is the wrong adhesive for a shower whatever its dry figure says, and one that survives water but not freeze-thaw is wrong for an external terrace. The set of four is the result; any one of them alone is a fragment.
They are classes in the requirements standard, EN 12004-1:2017, and an adhesive earns one by clearing the stated limits in each of the named conditioning regimes. The strength figures come from this method, so the class is a summary of a set of EN 1348 results rather than a separate property. Reporting one regime and letting it stand for the class is how a product ends up compliant on paper and not on site.
Because the method specifies it: the force increases at a constant 250 N/s, plus or minus 50, until the bond fails. Running the frame in displacement control instead makes the loading history depend on how stiff each assembly happens to be, so nominally identical specimens see different rates and the scatter grows for a reason that has nothing to do with the adhesive.
A modest one. Capacity is not the constraint — a tile of this size at a few newtons per square millimetre fails in single-digit kilonewtons — so what matters is a truly perpendicular pull, steady force-rate control to failure, and a load cell chosen for that range rather than for the frame. Conditioning capability is as much part of the requirement as the frame, since immersion, heat ageing and freeze-thaw cycling all have to run to schedule.
A pull-head bonded out of square, which peels one edge first and gives a low result with a misleading failure surface. After that: bonding adhesive that has not fully cured, so the head releases before the mortar and the test has measured nothing; slabs drifting from the standard specification or varying in porosity between batches, which reads as adhesive variability; and reporting a figure without naming the conditioning regime it came from.
Because porosity and surface texture govern how much water the substrate draws out of the adhesive while it sets, and that in turn governs the bond. Leaving the slab to whatever the laboratory had makes results incomparable between laboratories and between batches. The slab specification travelled with the method: it was EN 1323 while EN 1348 stood, and EN 12004-2 absorbed both in 2017.
Dak verifies against whichever standard the method names, and where a class applies our frames sit a class tighter than it asks.
| The method asks for | Dak supplies | |
|---|---|---|
| Capacity | Low. A small tile at a few newtons per square millimetre fails in single-digit kilonewtons, so capacity is not the constraint and a cell chosen for that range resolves far better than one sized for the machine. | Load cells from 1 kg to 60 ton on the Series 7200, and 0.5 to 100 kN on the Series 9000 |
| Force accuracy | unknown — no accuracy class could be confirmed for this method | ISO 7500-1 Class 0.5, verified to ASTM E4, DIN 51221 and BS 1610 |
| Gripping | Pull-heads bonded square to the tile faces, with a positioning arrangement reaching each tile in turn on a fixed slab | Our a fixture built for this method, built to the specimen |
| Environment | Nominally 23 °C and 50 % relative humidity, plus four conditioning regimes: standard conditions to 28 days, water immersion, heat ageing at 70 °C for 14 days, and 25 freeze-thaw cycles | 3009 series chambers, −150 °C to +400 °C — temperature only |
This page describes the method as practised. The governing text is the current edition from the issuing body. Tell us what you are testing and we will answer with the machine, the fixture and a quotation.
