Inline Extractor Fan - Does This Look Okay?

[flapjackboy]

Hi,

I joined the forum this evening as I'm after some advice, and hoping people here can help. I had an inline extractor fan installed in my loft yesterday, and after the electrician left, I checked the grill in the bathroom ceiling as it looked like it wasn't quite flush. It was just screwed into the plasterboard (without any plugs) and was loose, some of the screws weren't completely screwed in and the ducting was just pushed onto the grill, without being secured at all.

I sorted out those issues myself but it made me think - if the electrician did that on the parts of the installation I could see, what did they do with the bits I couldn't see? I went up to the loft and had a look this evening - after replacing some insulation the electrician had removed (I think to find somewhere to put their feet) and picking up the litter they had left up there, I took some photos (attached to this post).

I'd like to know if this installation is alright, because I'm not sure. The only reference I can really find it the domestic ventilation compliance guide from 2010, which states that the bends in the ducting should be at least the diameter of the duct width, which they aren't here, and there shouldn't be peaks and troughs in the ducting. The fan itself is not secured at all, just sat on top of the plasterboard - does that matter? The ducting could have been cut to length and hasn't been, so there's a lot of compressed ducting too. Is that an issue? The fan seems to be doing the job, so I'm wondering whether this is worth trying to put right or if I should just leave it.

Any thoughts, comments or advice would be appreciated. Thanks.

 

[JohnD]

it's rather untidy. I think you could do better yourself. If the board with the fan was moved a bit, you could run straight from the ceiling vent to the fan inlet, with a shorter, straighter piece.

Loops are prone to hold condensation.

 

[Alec_t]

The fan itself is not secured at all, just sat on top of the plasterboard - does that matter?

That might turn the plasterboard into a loudspeaker diaphragm! I'd mount the fan on a resilient layer to deaden fan-induced sound.

 

[flameport]

Ducting secured to the fan and inlet/outlet with cable ties or aluminium tape.
Duct as short as possible

If you want it to be as quiet as it can be, suspend the fan from some blind cord or thin nylon rope, secured to the timber above and looped through the holes on the base of the fan.

 

[JohnD]

The fan itself is not secured at all, just sat on top of the plasterboard

@flapjackboy

FFS, very shoddy workmanship. I thought from the pic it was on a bit of ply.

For a better job, get an offcut of (preferably) 18mm ply around 600mm square (but big enough to bridge over two of the joists) and a scrap of carpet underlay, and some big "penny" washers

cut the ply so it fits over two joists and is long enough for the fan

sandwich the ply with underlay on both sides (glue or staple to hold it in place while you are working)

drill near the corners (bigger than the screw diameter) and screw it down to the joists with a big washer under each screw head and the underlay between the joist and the board (this will prevent vibration noise passing) and screw the fan down onto the board on top of the upper underlay. If you want, you can use a bigger piece so you have something to stand or kneel on while working. Do not put it above the electrical light fitting or the ceiling hole as you may need access in future.

Cut the hose and lay it out so it is fairly straight and has no unnecessary loops

Your hose looks like it is the insulated type, which is not prone to condensation. If not, flop loft insulation over it.

If you need to buy any loft insulation, get the type treated with Ecose which does not shed irritant dust or fibres (it will be marked on the packaging).

p.s.
it looks to me like your existing loft insulation is pushed too far into the eaves and will block ventilation. This can lead to condensation in the loft. There should be enough of a gap to see daylight at each end and each side so there is a perceptible through-draught of fresh air.

 

[flapjackboy]

Thank you for all the replies, its really appreciated. I definitely have regrets about getting the particular electrician in to do this job, as I thought they cut whatever corners they could, so it's good to know that other (more qualified) people think it could have been a better job. The advice on securing the fan properly and adjusting the ducting is really useful, I'll go and get some materials tomorrow and sort it out. Thanks for the advice on the insulation too - I'll have a look at that tomorrow as well. The attached pictures were taken after sunset so it was dark outside, but I'll have a look during the day look for some daylight coming through!

 

[JohnW2]

... it looks to me like your existing loft insulation is pushed too far into the eaves and will block ventilation. This can lead to condensation in the loft. There should be enough of a gap to see daylight at each end and each side so there is a perceptible through-draught of fresh air.

... if it's anything like my house, those would be chinks of daylight known to some birds, squirrels and rats (and allied brethren!) as their 'front/back doors'

Wire mesh or suchlike may frustrate their access to such entrances to some extent.

Kind Regards, John