Best safe heater for attic

PoGee

Our attic is partially floored with good amount of insulation in rest. The attic area directly above the hall (hall is coldest area of house) is showing signs of condensation on new roof boards. I think they're called sarking boards. I could put a heater up there on a timer - is a skirting board the best choice? I don't want the insulation to catch fire.

grumbler

Floor insulation is there for a reason - to stop heat leaking from the house to the attic. The roof is not insulated and it will cost a fortune to heat the attic.

Do your best to stop moist air getting to the attic from the house in the first place. And make sure it's well ventilated. 

If the attic is ventilated and its floor is insulated, it makes no sense to heat it.

swingaloo

We had the problem of a lot of condensation in the attic. We  have had much better insulation put up there and also had those vents fitted on the roof. 

PoGee

Thanks for reply. The loft is ventilated with tile vents. There are 6 in total - 2 on each section of loft. There are also vents on soffits. I don't know why that one section has condensation ( I think it's condensation). The new velux window also has droplets of water. The window is on one of the dry sides of roof. It's a 3 bedroom semi. I'll get the roofer who installed the roof, to take a look after the new year but think that's what he'll say - it's a 'cold spot/area', causing condensation.

PoGee

So it it best to increase insulation and maybe ask for 3rd vent on that section of roof? I just went up and removed a layer of insulation from there, thinking it was blocking air flow 😕 - causing moisture on boards and window. The old roof was mouldy but didn't really see condensation. 

grumbler

PoGee said:

I don't know why that one section has condensation ( I think it's condensation). The new velux window also has droplets of water.

Because the warm moist air is getting to the attic from the house?

 I'll get the roofer who installed the roof, to take a look after the new year but think that's what he'll say - it's a 'cold spot/area', causing condensation.

The ROOF isn't insulated. The attic floor is. The roof is supposed to be cold. The better the floor is insulated, the colder attic is and the more likely you are to get condensation if warm air leaks to the attic from the house.

PoGee

I thought I'd insulated it enough to stop moisture. I didn't put in too much above bathroom area in case the shower cable caught fire. That might be where it's coming from.

grumbler

PoGee said:

I thought I'd insulated it enough to stop moisture.

Insulation stops heat, not moist air. Air leaks mainly through the loft hatch (gaps) and light fittings.

ThisIsWeird

PoGee said:

I thought I'd insulated it enough to stop moisture. I didn't put in too much above bathroom area in case the shower cable caught fire. That might be where it's coming from.

Lift the cable and place the insulation under it. Try and get some - as much as possible - insulation over the bathroom as well.
This velux, is it in the attic? If so, keep it cracked open on vent setting.
These are 'new' sarking boards? How much work was done to the roof? What ventilation was added? 
In general, unconverted loft and attic spaces should be kept thoroughly ventilated to keep them dry. Yes, this will make them feel colder, but that doesn't matter - it just needs to be dry.
Adding a heater is just not the solution. The amount of heating required to keep the moisture in the air instead of condensing out on cold surfaces would likely be silly, and an utter waste. 
1) Prevent, as much as possible, the warm moist house air from getting up to the loft. Make sure the hatch is well sealed. 
2) Insulate your ceiling. Keep the warmth in your house. Let the loft be naturally cold (and hot in summer!).
3) Ensure adequate ventilation in the loft area. Usually the through-flow from the eaves is enough - ie via the soffits - but slate and ridge vents can be added if necessary.
4) Don't be too concerned by short periods of isolated patches of condensation forming during colder climes. If it hangs around for weeks or months, or begins to stain or darken the timbers, then you may need to investigate further, but it isn't at all unusual for some cond to form at some points during cold weather.

ComicGeek

PoGee said:

Thanks for reply. The loft is ventilated with tile vents. There are 6 in total - 2 on each section of loft. There are also vents on soffits. I don't know why that one section has condensation ( I think it's condensation). The new velux window also has droplets of water. The window is on one of the dry sides of roof. It's a 3 bedroom semi. I'll get the roofer who installed the roof, to take a look after the new year but think that's what he'll say - it's a 'cold spot/area', causing condensation.

Installing a velux in an attic can cause problems with condensation. Depending on orientation, it can cause issues by allowing heat from the sun into the attic during the day, and then radiating out heat more quickly to clear skies at night time. Leads to much larger and quicker swings in temperature than attics without windows, and this in turn can increase issues with condensation. The glass is likely to be the coldest surface, so will likely attract the most condensation. 

If the hall area is the coldest, then likely this is driving warmer air across to this area, which is then condensing on the cold surfaces in the attic above.

Doesn't sound like moisture is being dealt with sufficiently, so look at how well the extract fans are working in the bathrooms.

Chickereeeee

PoGee said:

I thought I'd insulated it enough to stop moisture. I didn't put in too much above bathroom area in case the shower cable caught fire. That might be where it's coming from.

Do you have dowlighters in the bathroom? Older ones are often a path for warm, moist air into the bathroom. 
You should be careful of insulation covering a cable carrying high current, in case it overheats, but loft insulation is not flammable, if you are worried about that.