Home DIY

Insulation should be on the floor of the space. The attic should be about the same temperature as the outside. If it is warmer you will get condensation on the inside of the walls and the wood can rot or get mould.
Ensure the attic is vented as well to avoid excess humidity.
We use two types: large bundles that lie between the rafters or, in larger spaces, insulation blown in with a machine. The blown in kind is probably overkill for your mild UK climate.
The blown insulation is standard in Canada, we had minus 40C a few weeks ago.
We can get government grants to offset the cost of insulating, since it reduces energy consumption. Maybe you can get help there?

Thanks very much - that's exactly what I needed to know. I can get going on it at the weekend. I've seen videos of that blown in stuff- it looks horrible if you every have to revisit the area to do work on it!

I had a look for government funding, but to be honest I'd rather just buy a few of rolls of wool and get on it myself - because I need the space for storage (and it's fairly small) I'd unlikely be able to meet the recommended specs on depth of insulating material which I think might disqualify me.

https://www.toolstation.com/loft-flooring-legs/p44016 or similar?

The blown in stuff makes any work almost impossible.
If you are only doing a small area use the rolls. They are easy to lift up if you want to fiddle with wiring or light fixtures.

@Airhead cheers for the input. I've gone ahead and ordered the BQ integrated LED version and given they're about 50% cheaper than the next pricier non integrated version I ordered a spare. Cheers.

I'm not clear - is the loft conversion (middle bit) insulated at roof level, and not in the floor? Does that insulation come down the (presumed) wall with little door in? Is it in the roof and then just stops, so heat from the middle space goes through the storage to the outside, as well as heat from downstairs going up through the storage space to outside?

Thanks - they're a good idea.

It's only a crawl space though, and if I raise the floor then it will make it really hard to get anything in there :) a layer of wool between the joists, then board over the top is about all I can do if I want to keep the space usable as storage.

I think (assume) the walls and ceiling of the rooms in the conversion are cavity insulated.

Theres some insulation on the other side of wall with the little door in it, but none in the rafters behind that wall. There's nothing insulating behind the roof tiles for example. Any heat that ends up in the storage place will just disappeared away.

The previous owners builder was a cowboy - we've encountered several examples of his craftsmanship!

Console yourself with the graph half way down this: https://www.thegreenage.co.uk/what-is-the-recommended-thickness-of-loft-insulation/ and then improve things by adding the insulating properties of your boards?

Our loft space has 150mm insulation and boards over the joists - a neighbour (identical house) has something like 300mm and very similar heating bills but without the extra storage space...

I'd like to provide additional heating in my bathroom. I have a towel rail connected to the gas combi boiler however the room gets cold at the window end, which is far from the towel rail.

Mould is growing on the wall adjacent to the window.

My thinking is that a small horizontal electric radiator, controlled by a thermostat and timer, could keep the room temperature higher and this would help the extractor fan do its job better (warm air holding more moisture, and the walls being warmer thus discouraging condensation).

Does such a product exist that could fit in the available space (approx 700 wide, 300 high)? If so, what is it called? Should I be looking for an oil filled radiator, a small horizontal towel rail, something else...?

I'm assuming it will be installed by a sparky and will be on its own fused spur.

1 Attachment

Would upgrading the extractor fan be an option? If it's not on an overrun timer, that should help. Or beef it up to a higher volume one. I recently swapped out mine in our similar sized shower room to a much more powerful one and the difference is amazing. No steam no condensation whatsoever.

Thanks, but I'm not so sure upgrading will help. It's a relatively new 5" axial fan, and it is indeed on an overrun timer. (That said, what model did you install?)

I am planning to add louvres to the bathroom door as I feel that will help the fan pull more air. I'll do that first, of course, as it's cheap and reversible whereas the radiator option is more involved and costly.

Thats a large window for the size of room. If the glass isn't Low-U, maybe consider replacing it with a new double glazed unit. That will keep some more heat in.

Being patterned glass it should be easy to tell:-
Patterned pane inside is standard glass.
Patterned pane outermost will (more than likely)have a Low-U coating on the inner clear pane.

Inline mixed flow extractors probably move 3 times the air volume of the one you have in the window. If theres access above the ceiling to install the ducting and fan, vented outside then that could make a big difference. Especially if you were replacing the glass.

If only there was a way to get a fan anywhere but in the window... Unfortunately the window goes all the way up to the lintel. And the ceiling is lath and plaster directly onto joists, so no scope there. (If I run a vent between the joists I'll be arguably within the upstairs neighbour's property)
Glazing was replaced about a year ago, when the fan was installed (replacing the previous which was around 25 year old glazing plus non-powered vent). The outer pane is patterned glass.

I went from wall mounted to in-line in the ceiling. I think on paper the extraction rate quadrupled. Was defo overkill, but after a bit of a mold outbreak in the room above, I didn't want to muck about. It's a acm100t.

I don't know how much variance there is in terms of power between window mounted extraction fans. If there's not much between different models than ignore my suggestion.

Maybe a dehumidifier could help?

I've got a manrose wf120 something, which extracts 36l/s. So on paper your fan does 61l/s which is better. But not dramatically so, as it would be going from a 100mm window fan (23l /s).

So yeah basically I've got the fan in the only feasible location and it's drawing air out at the maximum feasible flow rate. Not surprisingly since i specified it :)

Not planning on changing the glass, as I had it done to fit the fan, and not planning on dropping the ceiling level because I'd have to change the window including its external appearance and that would probably require permissions as I live in a conservation area, and also be a lot of work.

I am struggling to find the right product, though. The closest I've got is a "skirting heater" but I've not found one that is small enough and rated for use in a bathroom.

I'm wondering if a wall-mounted vertical radiator would be better.

The idea of it being electric is to avoid over-using my central heating when I only want to heat one room.

Glazing was replaced about a year ago, when the fan was installed (replacing the previous which was around 25 year old glazing plus non-powered vent). The outer pane is patterned glass

It sounds like you probably covered the new low-u glass and a ducted fan is a non starter.

Electric underfloor heating mat?
Dimplex tubular heaters come in 1, 2, 3 and 4ft sizes and can be stacked?
https://www.dimplex.co.uk/product/ecot-3ft-tubular-heater-thermostat

Any heater in this position is going to be constantly fighting against the cooling effect of the window, particularly immediately around the existing extractor. It’s a good idea but I doubt what you have in mind will work in practice.

Can you better seal the shower cubicle in any other way? Or fit an additional extractor in the cubicle, perhaps boxing the ducting in?

Sorry to say it but the best chance you have here is to replace the window with a smaller one and fit a suspended ceiling with a ceiling extractor or two.

To disagree with ^ I think where you've marked is exactly the right place to put a heater, to mix with cold air from the window and reduce condensation around there.
The obvious product to me would be a small electric towel rail?
Also, I found simply wiping down condensation after a shower really helps.

Thinking about this a bit more you could try fitting the most powerful extractor you can get your hands on. You also need to think about wind direction on the external face of the window, if the wind is constantly blowing against the window the fan is likely to be a lot less efficient.

Here’s my rationale:

The problem is that warm, moist air is being pulled actoss the room and towards a large cold surface. This cools the air and causes the moisture to condense on the window and wall. What @Cupcakes is asking of a heater is to (a) reheat the air, (b) reabsorb the moisture on the wall and window and (c) create sufficient thermal convection current to overcome the existing downdraft (which is increased by the placement of the fan).

I just don’t think a little electric towel radiator is going to do that and the problem needs to be tackled at source. But if anything, putting a heater above the window might keep the air warm for enough time for the extract to do its job might be better.

Another option perhaps is to find some kind of hot air fan aimed up at the window, or even a demister like the electric circuit you have in a car windscreen? Idk if that exists but those might work better imo.

Edit: just try a bigger fan first ;)

Any ideas as to why the new extractor fan I've installed in my bathroom doesn't work? The old one packed in, presumably the motor, so I've replaced with a newer one and attached the only two wires correctly. This new one doesn't have a pull-cord whereas the old one did, and now it doesn't turn on at all with the lights like the last one did.

I'm pretty clueless when it comes to DIY so I don't want to go messing around with shit that might/will kill me, just wondering why such a simple job doesn't work

In short, it's not a simple job. You should have a switch wire which activates the fan as well as the line and neutral to provide the power. Do you have an isolation switch for the fan outside the bathroom? I'm asking to try and judge the age of the installation.

How do you want your fan to operate? Switch on with the lights, humidity detection, motion detection?

Not really fussed how it comes on, just want it to take air out when using the shower.

The old fan definitely only had two wires going into it, and the new fan only has two connections so the only two wires are attached correctly.

3 Attachments