Very confused about building regulations and might need to replace ceilings?

[ihatefobs]

Hi all,

I am getting a dormer done in east london, the plan appraisal has flagged up that 1st floor ceilings need to be fire rated 30 minutes. Builder is now under the beleif that the existing ceilings will need to be taken down and replaced with 30 minute fire rated plasterboards. He has mentioned he has not been made to do this anywhere else before and is suprised about this regulation.

I then spoke to the building regs person and he mentioned that it was highlighted in the plan appraisal but if the steels have been painted in fireproof paint (which they have) and chicken wire is laid for existing ceilings then no further measures are needed. Other than the obvious fire doors and alarms etc.

Now the issue is the builder is saying he's not heard of the chicken mesh thing before and he's not even had to ever replace full ceiling with fire plasterboard and is saying we will need to replace the ceilings to fit 30 minute plasterboard. This is coming to an extra 5k that I just can't afford plus the extra mess and time. I spoke to the architect and he is saying usually this is for a flat conversion which I am not doing. Simply adding a dormer to a 2 storey house. He has said that as long as the steels are painted white then the chicken mesh is not needed?

So I am wondering has anyone before had to replace ceilings to meet fire regs and also regarding the chicken mesh if anyone can provide insight on how this is laid is it on the underside of 1st floor ceiling or if it is on top of the joists in the loft and then the existing ceiling is below this?

Please ask me any questions you need I'm also trying to reach out to the building regs and architect but no luck at the moment.

I think my current ceiling are either plaster or plaster lath?

What is the mesh for? Online I can see that it is usually used to keep the floor insulation in place? If so would that not be easier to do than taking down all ceilings and redoing them?

Many thanks

 

[Wayners]

2007 bungalow loft conversion.

Downstairs ceilings packed with 250mm ISH rockwool then chicken wire from screwfix stapled to beams.
Then standard plasterboard over.

Idea being if fire takes down plasterboard the chicken wire holds the rockwool in place protecting upstairs floor.

Upstairs was superfoil with foil backed plasterboard fitted over.

All I can say on subject. Was hit or miss those that knew about this though.

 

[ihatefobs]

2007 bungalow loft conversion.

Downstairs ceilings packed with 250mm ISH rockwool then chicken wire from screwfix stapled to beams.
Then standard plasterboard over.

Idea being if fire takes down plasterboard the chicken wire holds the rockwool in place protecting upstairs floor.

Upstairs was superfoil with foil backed plasterboard fitted over.

thanks for replying

how it currently looks is:


Loft floor - fire flooboards
new joists for loft
insulation between existing joists
lath and plaster ceiling from 1st floor.

So you would be saying to make it meet regs it would be

loft floor - fire floorboards
new joists
insulation
chicken wire
old joists
lath and plaster ceiling?

 

[freddiemercurystwin]

Surely you know what your existing ceilings are, you can see it from above? Assuming it is L&P the reason for the chicken wire is in case the lathe and plaster ceiling fails (ie falls off) in the event of a fire, then the chicken wire will retain the mineral wool and the integrity of the floor is maintained. There's no way to determine the condition or thickness of existing L&P so it's an unknown. You fit your chicken wire from above, staple it or similar to one joist side then push it down into the gap between the joists and up the side of the the next joist so as to create a craddle for the insulation. This is standard stuff for loft conversions where the ceilings are L&P, your architect and builder are both lemons.

 

[ihatefobs]

Surely you know what your existing ceilings are, you can see it from above? Assuming it is L&P the reason for the chicken wire is in case the lathe and plaster ceiling fails (ie falls off) in the event of a fire, then the chicken wire will retain the mineral wool and the integrity of the floor is maintained. There's no way to determine the condition or thickness of existing L&P so it's an unknown. You fit your chicken wire from above, staple it or similar to one joist side then push it down into the gap between the joists and up the side of the the next joist so as to create a craddle for the insulation. This is standard stuff for loft conversions where the ceilings are L&P, your architect and builder are both lemons.

you're right they are both lemons and It is sad that I have to come here and try to do my own research with the help of people.

I have confirmed the ceiling is lath and plaster as I remember a few years ago in another room someone put their leg through whilst in the loft when the loft was not converted. That room now has plasterboard. All other rooms are still L&P.

If I have understood you correctly as long as the steels are painted and the insulation is placed on top of the chicken mesh to hold it in place this should meet the regs for the loft? This also does match with what the inspector said though his wording was quite odd.

Just to confirm with you again, so they would staple the chicken mesh to the new joists then push it down into the gaps till it gets to the L&P and makes a cradle as you say between two joists then on top of this they will place the insulation(in the cradle).

As the structure is already done im hoping this can be done only where it is now possible to place the mesh for example as rooms are partioned some areas are no longer reachable. All the floorboards however can be picked up so majority of the joists are visible and reachable within the partioned rooms

thanks.

 

[freddiemercurystwin]

Correct, though the mineral wool should be everyehere the L&P is.

Skip forward to about 5.30:

 

[^woody^]

Chicken wire is standard. A builder who's not heard of it is non-standard.

You could instead, potentially upgrade the floor deck with a layer of mdf.

 

[ihatefobs]

Hi All,

Getting a dormer loft done. All ceilings on 1st floor are lath and plaster. I wanted to know if all these ceilings need to be upgraded to meet fire regulations or is it just the area which connects to the protected escape route which requires upgrading? The method of upgrading would be to place chicken mesh in the joists above and fill with insulation. I understand it is obviously best to do the all ceilings in all rooms. But in terms of actual technical wording in line with regulations I wanted to know if regulations require all 1st floor ceilings including bedrooms to be upgraded or only the ceiling area where the protected escapte route is e.g. where the stairs are. Along with this fire/smoke alarams are being placed on all floors and also firedoors and frames are being installed on all doors within the escapte route.

many thanks.

 

[JuddlyFire]

Hi ihatefobs,

Let me try to help clarify based on the actual regulations.

First off, the key point here is that Approved Documents provide the standard approach to meeting Building Regulations, but crucially: "Alternative approaches are possible but they should be discussed and agreed with a building control body before building work starts." ↗ This is important because it means there can be more than one way to meet the fire safety requirements.

From what you're describing about chicken wire (properly called wire mesh or mineral wool retention mesh), this is indeed a standard method used in loft conversions with lath and plaster ceilings. The purpose is to retain the insulation in place if the lath and plaster fails during a fire, maintaining the 30-minute fire separation between floors.

The mesh should be installed from above:

• Stapled to one side of the joist
• Pushed down into the gap between joists
• Brought up the other side to create a "cradle" for the insulation
• Insulation (typically 100mm+ mineral wool) is then placed on top of this mesh

Regarding your specific question about whether all ceilings need upgrading or just the protected escape route:

The regulations generally require fire separation throughout the entire floor area, not just along the escape route. This is because the fire resistance requirement (30 minutes) applies to the structural separation between floors to prevent fire spreading vertically through the building.

Your building control officer is correct that with properly installed fire protection to the steelwork AND the mesh/insulation system above the existing lath and plaster ceilings, you shouldn't need to replace all your ceilings with fire-rated plasterboard. This approach is specifically recognized for existing lath and plaster ceilings in loft conversions.

A few practical points:

• The mesh method is significantly less disruptive and cheaper than replacing all ceilings
• It's absolutely standard practice - any builder claiming they've "never heard of it" hasn't done many proper loft conversions
• You'll need to ensure the mesh is installed throughout all areas with lath and plaster ceilings, not just where it's convenient
• Your fire doors and alarms are separate requirements that still need to be in place

If your builder is still resistant, suggest they check Approved Document B (Fire Safety) - specifically the sections on loft conversions. The mesh method is well-documented there as an acceptable solution for existing lath and plaster ceilings.

Hope this helps clear things up - it's frustrating when professionals don't know the standard requirements, but you're right to push for the less disruptive solution that meets regulations.