How Bodged is My Kitchen Extract

[AkiraDIY]

I had my kitchen extract ducting replaced as it was done badly and I think it's been bodged again. Some pics attached. What are the regs for kitchen extract ducting?



I have no idea why they decided to cut a 2ft of the PVC pipe to replace it with 5ft of flexi. Surely that flexi is too long?



They've duct taped the end of the flexi to a bit of wood screwed into a joist. Looks absolutely awful.

That blue fan doesn't actually work. I don't know if they broke it or if it never worked. There's a unbranded vent-axia type ceiling extract in my kitchen that does seems to work. Although I doubt it has the guts to achieve the required airflow through all those bends.

Should I tell the contractor that the job isn't acceptable and give them a chance to fix it?

 

[conny]

Have they connected the white flexible ducting to the grey/silver flexible ducting, which is connected to the blue fan, which you say doesn't work?
It certainly looks a mess, and that junction box with the lid missing needs sorting. It looks as though there are pieces of flex coming out of it, (could be camera angle), with cut off ends. What's with the 'cable entry' FCU and the small box next to it? Why are they screwed to a loose piece of board?

 

[AkiraDIY]

Have they connected the white flexible ducting to the grey/silver flexible ducting, which is connected to the blue fan, which you say doesn't work?
It certainly looks a mess, and that junction box with the lid missing needs sorting. It looks as though there are pieces of flex coming out of it, (could be camera angle), with cut off ends. What's with the 'cable entry' FCU and the small box next to it? Why are they screwed to a loose piece of board?

Yeah, the grey flexi is joined to the white flexi (there's a bit of pipe inside by the feel of it), and the whole thing is taped to a 2x4 screwed into a joist.

The blue fan doesn't look like it gets power. It's made by "Roof Units Group", which I've never heard of and I'm guessing is super old?
The white cable of the blue fan seems to have a lot of cores and goes into those two white boxes on the plank of wood. That plank of wood was what was supporting the old duct. Only that, and it got wet it wasn't sealed at the roof penetration so the old duct dropped. Now the wood is freestanding, only connected via the cables going to the blue fan.


This is on the other side, the "infeed" to the blue fan. I doubt it's effectiveness.

The junction box doesn't seem to be in use, every cable going to it is cut. I'll double check and remove it next time I'm up there or get a lid on it.

 

[jeds]

It's a bodge, a mess and technically incorrect. Fan ducting running through roof voids must be fully insulated or should have a drain. Else it will run with condensation and eventually fill up the u-bend at the bottom and eventually water will run into the fan housing.

 

[conny]

If you get the same people back, (as, rightly you should do because it's a mess), they will probably refuse to come back or just make another mess.

I'd be tempted to ask around to see if any family/friends could recommend someone that could do this properly.

 

[AkiraDIY]

Annoyingly, I asked my factor for a recommended roof contractor and that's what I got. The person I arranged the job with seemed to be quite pleasant, appeared more competent than the ones carrying out the work at least. I'm going to send them some pictures and ask if they think that is acceptable.

I don't think I can just tell the contractor that their work is dogs**t and I'm refusing to pay. I imagine I need to give them a chance to fix it and clear out the rubbish as agreed first (the old duct, plastic wrappers, offcuts, etc are just thrown around the place, including onto my neighbours part of the loft space).

I'm debating whether or not I should try and get power to the blue fan or just remove it entirely since it's adding two 90 degree flexi connections. It would be less resistance for the ceiling extract that is working if I got rid of it.

If the contractor doesn't fix it properly, I'll probably remove all the flex and the blue fan (unless I get it working) and replace it with some more PVC ducting and install a condensate drain somehow (not sure where it will drain to yet as it's fairly central in the loft). The black PVC duct that the contractor put is at quite a high level so insulating it myself is probably unfeasible.

 

[robinbanks]

Equally concerning is the state they've left the loft insulation in.. it needs an upgrade, by the way. "100mm of old, dirt laden wool between the joists" doesn't cut it..

 

[AkiraDIY]

Equally concerning is the state they've left the loft insulation in.. it needs an upgrade, by the way. "100mm of old, dirt laden wool between the joists" doesn't cut it..

I believe the insulation piles were created by a sparky who rewired the house before I bought it. Only discovered the state of the insulation after chasing down some water ingress. Haven't gotten round to replacing it yet as I'm using part of the loft for storage and the cold water mains + central heating pipework could do with some attention.

I think I can get all pipework outta the loft as it rises up in my bathroom, goes across the loft and drops down in the kitchen, and in the kitchen it goes under the floor back towards the bathroom. But that's a future project. Kitchen extract first

 

[foxhole]

Pointless having a ceiling mounted fan in a kitchen, (has no grease protection) .Needs an extractor fan unit over the oven to remove moist air and kitchen smells and need to be rigid plastic or foil flexi to resist the hot air damage above a stove.

 

[AkiraDIY]

Pointless having a ceiling mounted fan in a kitchen, (has no grease protection) .Needs an extractor fan unit over the oven to remove moist air and kitchen smells and need to be rigid plastic or foil flexi to resist the hot air damage above a stove.

I also have a over cooker hood with grease and carbon filters re-circulating internally. If I didn't have a 3.2 meter ceiling height, I'd be looking into getting the hood ducted to outside too. But I do so I'm not.

My kitchen is internal (windowless) so building regs require a ceiling extract. Whether you think it's pointless or not isn't the question I'm asking. It's the system I have and it's what I need to work with. My question is about the quality of the work, specifically what exactly I should get the contractor to fix vs what is considered acceptable.


Currently outwith the work on the roof which looks acceptable to my untrained eye, everything between the black PVC pipe secured to the ceiling joist to the "outfeed" of the broken blue fan is an utter shambles and needs to be done again.

This is the list of what I've got that they need to fix so far:
- The white flex & PVC is 100mm diameter but the outfeed to the blue fan is 150mm. Could be better or the blue fan just bypassed.
- The total length of flex used is too long and not cut and stretched appropriately
- The method used to secure the flex is a joke
- They need to clean the rubbish as agreed

What I'm unsure if they should fix is:
- Duct should be insulated or means for a condensate drain provided. However, I'm not sure where the drain would go and the original system didn't have either of these so maybe not their responsibility?
- Blue fan is broken, unsure if that was the case before or if they broke it. Probably don't want them looking at it, might just ask if they can bypass it?
- Don't know if I can request that they use solid duct for the entire thing as indicated in the contract and ditch the flex.

The original contract was for them to:
-Remove approx. 6 tiles surrounding the old metal vent on roof. (I know they removed 1 as it was smashed, tape&mastic repaired previously, now thrown onto my neighbours side of the loft ontop of their brand new insulation)
-Remove the vent and supply and fit a new macflash and 4" UPVC pipe. (you can see what they done, the final bill was amended to say UPVC pipe and a flexible pipe)
-Supply and fit approx. 6 new Marley Ludlow tiles surrounding the vent. (final bill amended to say 3 tiles although I only see 2 and the wrong colour at that. One full tile and two pieces either side of the new vent. No change in final price but I assume they're cheap enough to be negligible)
-Tidy site area on completion. (Not done as expected of lazy builders. Rubbish just left everywhere as they gambled on me not checking since access is not straightforward)

 

[Ivor Windybottom]

Everything is wrong with it. That tape lasts about 2 years until the glue dries out and flakes off. Once it falls apart it will be blowing into the loft, you won't know and it will make the loft drip with condensation.

It needs insulation to prevent condensation within the ducting and/or a condensation trap, otherwise you'll get drips into the room from the grille.

The ducting is just terrible in every way. Rigid ducting would be vastly preferable, ideally pre-insulated. Done with care by someone who isn't an utter cowboy.

 

[noseall]

Rigid ducting would be vastly preferable, ideally pre-insulated. Done with care by someone who isn't an utter cowboy.

Possibly. Depends on the direction etc. Flexi-hose is better for quick changes of direction.

However, that location is unfortunate, in that the extractor is located beneath the tallest part of the roof. Meaning the duct run is always going to be long. We strive to keep a duct run as short as possible, where it passes into a cold zone. If this isn't possible, then it is important to wrap the duct with insulation.

A long vertical run like that will likely need a condensation trap.

 

[noseall]

That tape lasts about 2 years until the glue dries out and flakes off.

Duct tape is designed for that very job.

 

[AkiraDIY]

Possibly. Depends on the direction etc. Flexi-hose is better for quick changes of direction.

However, that location is unfortunate, in that the extractor is located beneath the tallest part of the roof. Meaning the duct run is always going to be long. We strive to keep a duct run as short as possible, where it passes into a cold zone. If this isn't possible, then it is important to wrap the duct with insulation.

A long vertical run like that will likely need a condensation trap.

I would have preferred if the original ducting went horizontally and exited via the eaves with a slight decline instead of vertically via the roof but I can only make do with what I have.

Insulating the pipe is probably going to be annoying, expensive, and unable to prevent condensation either way due to the length, like you said. A condensate trap is probably best but the problem with this is I'm not sure where the condensate drain could go. Being beneath the highest point of the roof also means it's furthest from any drain points.

In the first picture, where that square of light is, it leads down into a storage cupboard where the kitchen waste drain and an anti-siphon trap pass through before dropping below floorboards. I could probably route a small diameter plastic tube from the extract duct to that drain. It would be 2-3m of horizontal travel in the loft (maybe slight decline depending on where the trap is located), then vertically down 3m+ to the drain.

Would that suffice or is small diameter tubing (3-5mm ID) just waiting to be blocked?

 

[noseall]

Insulating the pipe is probably going to be annoying, expensive, and unable to prevent condensation

Wrap it in wool secured with more duct tape and be careful not to crush the hose. Piece of cake. It all helps.