Shaft Closing Process: 5 Steps | Simfy Firesys Hyderabad
Shaft opening prepared with steel rebar before fire mortar — Simfy Firesys
Our methodology

Shaft closing:
the 5-step process

Preparation, mesh, wool, mortar, finish. Skip any one and the seal looks complete while holding nothing.

Book a Passive Fire Audit
Our ServicesCall us
Finished fire mortar seal photographed before the shaft closed
Step five: the photographThe last thing we do on every seal, because after this nobody can check it.
The method

Five steps, in this order,
every time.

These are photographs from our own shaft closing projects, not illustrations. Tap any one to see it at full size.

Why the order matters

What happens if a step is skipped.

Every one of these shortcuts saves half a day and costs the seal its rating. This is what we find when we audit somebody else's work.

01
No rebarMortar has nothing to grip across the opening. The slab cracks the first time the building moves, and the crack is a smoke path.
02
No meshWet mortar drops through before it sets. What is left is thin at the edges — exactly where fire tests it first.
03
No mineral wool, or packed looseAir gaps around cables. Smoke does not need much: a loose pack behaves like a small open hole.
04
Mortar applied thinner than specifiedCheaper and faster, and it changes the fire rating the seal was tested to. This is the single most common shortcut we find.
05
No photograph, no recordEven if the work was perfect, nobody can prove it. In an audit, undocumented work is treated the same as work not done.
Quick reference

The five steps, in one table.

StageWhat happensWhy
Step 01Preparation & rebaringWe clean out the opening and fix steel bars across it. The bars are what the mortar holds on to.
Step 02Mesh backingFire-rated mesh goes over the bars. It stops the wet mortar from falling through while it sets.
Step 03Mineral wool packingHigh-density mineral wool is packed in tight. It takes the heat and fills the gaps around cables.
Step 04Fire mortarAmeetuff fire mortar is applied to the thickness the tested system asks for. Not thinner.
Step 05Final seal & photosA top coat closes the surface. Then we photograph it and write down what went in.

Scroll sideways on a phone.

The point of it all

What a sealed shaft buys you.

Not theory — this is the difference the five steps make on the night it matters.

OPEN SHAFT Fire keeps climbing
Floor 12
Floor 11
Floor 10
Fire starts here

A cable shaft that is not sealed is a chimney. Smoke and heat reach the floors above in minutes, long before the flames do. People three floors up are in trouble and they never saw a fire.

SEALED SHAFT Fire stays on one floor
Floor 12
Floor 11
Floor 10
Fire starts here

Seal the shaft at every floor and the fire is boxed in. Everyone above gets the time the stairwell was designed to give them. That is the whole of it, and it is all done before handover.

Fire and smoke Fire stop mortar seal Cable / pipe shaft
FAQ

Questions about the process

?
How do you prove the mortar went on thick enough?We photograph the seal at each stage and record the depth achieved against the tested system reference. The project file lists location, product, thickness and date.
?
Does the shaft need to be empty first?No, and it almost never is. The work happens around live cables and pipes. What we do need is safe access to the riser and agreement on when we can have it.
?
How long before the shaft can be used again?The mortar needs its curing time before the finish coat, which is usually overnight. The riser is not out of action that whole time — only the working face is.
?
What if we need to re-open the seal later?Tell us before we start. Where a riser is going to change, we use a re-enterable system such as pillows instead of a solid mortar seal, so nobody has to break it.

Want your shafts checked before you spend anything?

We will look at what is already installed, photograph it, and tell you which floors are actually a problem.

Book a passive fire auditCall +91 99088 07007