1cm gap under front door - New Build Flat

benssson · 30 Nov 2011

Hi everyone,

we've got a 1cm or so gap under our front door probably due to shrinkage. the flat is a new build with the front door leading into the communal corridor. The warranty from the builders is due to run out in 4 months so I'm keen to get issues resolved. Is this something they should fix? Is it a fire risk/building regs compliant?

Thanks!

Chu

freddiemercurystwin · 30 Nov 2011

10mm is pretty normal for an internal fire door. With regards to fire safety there is a negative pressure at the bottom of doors during a fire meaning cool air is sucked out of the room at the threshold (not the other way round). That's why there is no need for intumescent strips at thresholds, at least on doors with a 60 minute (or less) rating that is.

Graeme · 1 Dec 2011

I had the exact same problem when moving into my new build a few years ago which was at least 15cm gap. I bought an auto seal from exitex which sits flush on the door when it is closed but when you open the door the top of the seal is hinged so opens 45 degrees when the door opens inwards, preventing the seal catching on indoor carpet & door mat. It really improves the appearance of the front door now as you used to see the light from my hall when in the corridor. To finish off the inside of the door I just put a length of brush strip but set it so that it does not touch the carpet at all, it was just to cover the unsightly gap.

http://www.exitex.com/WeatherBars/PartInfo.aspx?PartRef=1.01.016.&referral=weatherbarwbar_i

freddiemercurystwin · 1 Dec 2011

Graeme said:
I had the exact same problem when moving into my new build a few years ago which was at least 15cm gap.

Jeez what sorta builders would leave a gap that big, I mean that's just sloppy workmanship!

Graeme · 1 Dec 2011

Oops, I meant milimetres!

steve61 · 2 Dec 2011

You can get a fire door drop seal which is routered into the bottom of the door. When closing the door it seals the gap. Just google "fire door drop seal".

Steve

freddiemercurystwin · 2 Dec 2011

steve61 said:
You can get a fire door drop seal which is routered into the bottom of the door. When closing the door it seals the gap. Just google "fire door drop seal".

Steve

Why? They're just a scaremonger product recommended and fitted by Unknowledgeable's.

steve61 · 2 Dec 2011

freddymercurystwin said:
steve61 said:

You can get a fire door drop seal which is routered into the bottom of the door. When closing the door it seals the gap. Just google "fire door drop seal".

Steve

Click to expand...

Why? They're just a scaremonger product recommended and fitted by Unknowledgeable's.

I agree, it's not necessary, but it might put the questioner's mind at rest. If it's the draught which is the problem then one of those cuddly snakes will do it...

benssson · 3 Dec 2011

Thanks for all the info!!

I'm not really worried about it being a fire risk to be honest, just wondered if it was a requirement for the builders to fix. I'll look into getting some sort of under door seal/weatherbar/cuddly snake for it as the whistling noise when we open the windows and the light from the outside corridor can be very annoying.

Thanks again everyone!!

^woody^ · 3 Dec 2011

BS 4787 (Internal and external doorsets and frames) would apply to this work, and states a clearance of 3mm to bottom of doors.

The only exception would be on a bathroom or utility room or suchlike, where there is an extract fan, in which case there could be a gap of 10mm to allow air into the room

freddiemercurystwin · 3 Dec 2011

^woody^ said:
BS 4787 (Internal and external doorsets and frames) would apply to this work, and states a clearance of 3mm to bottom of doors.

It may well do ^woody^ but hundreds of tests have proved a 3mm gap at the bottom will add nothing to the smoke resistance of the doorset. Common sense reigns here for once.

^woody^ · 3 Dec 2011

If the door (any door) has an excessive gap, then its not to the required standard, and the OP should get this sorted out under warranty

In any case, 10mm might be acceptable for an internal fire door (within a compartment of a flat), but not for a front door of a flat to a communal area, and not acceptable for a door intended to offer smoke protection too ... as flat front door would - its 3mm (+/- 1mm) in that case

freddiemercurystwin · 3 Dec 2011

OK ^woody^, ignore all the research into how smoke behaves.

^woody^ · 3 Dec 2011

What , do you mean something like from .... BS 5588 (Fire precautions in the design, construction and use of buildings. Managing fire safety) and BS 8214 (Code of practice for fire door assemblies) which require that fire rated doors should have no more than a 3mm (+1mm) gap at the bottom?

Both of which are referred to in Part B2

Or some thing like from TRADA ...

"Although it is not necessary to fit intumescent seals at the threshold of a fire door, a smoke seal is more necessary"

or

"The leaf/frame gap should be controlled to a maximum of 4 mm"

With regards to smoke, there is hot and cold smoke and each behaves differently. Most deaths from a fire are from asphyxiation, caused by inhalation of smoke, and greater emphasis should be given to controlling cold smoke leakage ..... including at the threshold

In addition Part E (Passage of Sound) states that seals should also be provided at the threshold where practical

But above all, if it was your front door, would you leave it, sort it out yourself, or get the builders to do their job properly?

freddiemercurystwin · 3 Dec 2011

Sure you're looking at the latest BS 8214 ^woody^?

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1cm gap under front door - New Build Flat

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