Bats in the belfry

[Pford75]

Ok...well not quite the belfry...but we do have a bat problem.

We've always had bats in the attic of the main house and they have never really proved to be a problem. However, following our recent burglary in our outbuildings, we were obliged to alarm these as well. The problem is that bats seem to be getting in to the eaves and then the roofspace and since the barn is open to the roof, they set off the sensors. There's a limit to the number of 3am false alarms one can tolerate.

I am aware that bats are protected, so haven't done anything to impede their ingress. Does anyone happen to know what the rules are in this sort of situation? I need to be able to secure the space and have explored all my options with the alarm people (laser beams on all windows were the only option they could suggest, but these would be prohibitively expensive).

 

[AMc]

We have bats that breed in our roof which means you have to keep the windows closed at night in summer- a pain. In previous years they've found their way into the house which has stumped me and the volunteer from the Bat Conservation Trust until this year when I worked out they were mistakenly coming into the exhaust for the bathroom extractors and getting in that way. I've bunged up the vent for now and will fit a grill at the exit point in the winter when they go away to hibernate.
The BCT volunteer was quite clear that I wasn't expected to put up with bats in my living space but must leave the loft roost and entrance points, unaltered and undisturbed. I would imagine, but I couldn't offer a legal opinion that you won't be able to block access to a bat roost in your outbuildings without applying for the relevant licences as that seems to be specifically what the law is there to prevent.

Some relevant links.
http://www.bats.org.uk/pages/living_with_bats.html
http://www.bats.org.uk/pages/bats_and_the_law.html

My first thought would be to explore options with the insurance company as to alarming the buildings. You can't be compelled to break the law but then I suppose they aren't compelled to offer you a policy either.

Can you use contact sensors on the entry points to the outbuildings?

I thought PIR sensors could be adjusted to ignore small animals (up to cat/dog size)?

The BCT have been quite willing to help in the past, so a phone call "about a property you're looking to buy" might get you some advice?

 

[MdB]

I thought PIR sensors could be adjusted to ignore small animals (up to cat/dog size)?

Dogs / cats will generally be on the floor, a considerable distance from the sensor. A bat can fly very close to the sensor and will produce a signal of equal strength to a human further away. I doubt it will be possible to adjust the sensitivity to detect humans but not bats.

 

[worms]

Could you net the underside of the roof trusses, so that the bats don't get into the alarmed space?

 

[Feltwell]

I thought PIR sensors could be adjusted to ignore small animals (up to cat/dog size)?

Dogs / cats will generally be on the floor, a considerable distance from the sensor. A bat can fly very close to the sensor and will produce a signal of equal strength to a human further away. I doubt it will be possible to adjust the sensitivity to detect humans but not bats.

Quite so - a spider can set off a PIR sensor, believe it or not. My in-laws, who ran a security company, had problems occasionally with spiders inside PIRs.

Why not just have contacts on the doors & windows as AMc says? That's all that is generally advised for outbuildings.

 

[chuckey]

i know someone who is about to start a barn conversion which has bats about it. They had to pay for a bat survey (£600), to find three bats insitu. They are living in an outhouse which will be demolished on the condition that a special part of the loft will be reserved for the bats with an entrance. A bat inspector (£700) will have to come along and be part of the buildings signing off. So 3 bats @ £1300 for the pack, looks like a bargain to me (+ cost of roof modifications).
Frank

 

[jocelyn plummer]

Oh dear Pford, you and insurance policys do not make the best of friends!!
catch 22 again, no cover unless you install expensive security system.
Some years ago We did that in one of our houses, linked straight to Police Station. Cost a fortune to install and maintain. The first incident which caused the Police to arrive in 3 cars at top speed was simply the security system engineer testing the alarms and forgetting to tell the monitering station that he was doing so. The second time I pressed the panic button because an intruder had come into the conservatory. ( i slammed and locked the connecting door and he ran away). I waited for my 3 minute response, which did not happen. After 10 minutes I rang 999 and was told that they had no alarm from our address, but they would send somebody out. 40 minutes later a police officer arrived on a motor bike and told me that he was really a dog handler-------- after hitting the roof with all concerned it turned out that the monitering station had not given the police the correct URN number for our address!!!!!!!!! Durrgh. All particularly bad as OH was in a sensitive military appointment at the time, and we were only a minutes walk from our local Police station. So, never again! However, it will be interesting to see how your company wriggles out of interference from Bats-- don't you have to pay for false alarms if more than 3? Best of luck!

 

[LadyArowana]

Would it be possible to install some sort of netting below the roof that would stop them getting into the main barn space and setting off the sensors? Using something suitably dense, like the black mesh used to shade greenhouses for orchids, the bats would see it with their sensory system.

 

[worms]

Would it be possible to install some sort of netting below the roof that would stop them getting into the main barn space and setting off the sensors? Using something suitably dense, like the black mesh used to shade greenhouses for orchids, the bats would see it with their sensory system.

Ahem! I think I already said that! Great minds, fools etc!

 

[Pford75]

Thanks for all the suggestions.

The problem with securing the outbuilding is that it has two doors (both of which have contacts), but there a several windows (some of which are non opening ones) which can only realistically be secured with area detectors internally. AIUI from the alarm company, a monitored alarm now has to have a 'two stage' system where a perimeter alarm can be set into 'guard' mode allowing 30 seconds after activation before trigger. Area alarms are in permanent 'alarm' mode and will trigger immediately. Our area detectors are dual technology..ie. they combine both PIR and Microwave.

I'd always understood that if bats are present, it is not permitted to block the entrance/exits they are using. Nevertheless, I have added a temporary 'trap door' over the stairwell between ground floor and upper floor which should prevent them getting into the alarmed area downstairs.

No false alarms for several nights, so fingers crossed have solved the problem.

 

[FamilyWiggs]

House a cat in the outbuildings?

 

[d49xc]

i know someone who is about to start a barn conversion which has bats about it. They had to pay for a bat survey (£600), to find three bats insitu. They are living in an outhouse which will be demolished on the condition that a special part of the loft will be reserved for the bats with an entrance. A bat inspector (£700) will have to come along and be part of the buildings signing off. So 3 bats @ £1300 for the pack, looks like a bargain to me (+ cost of roof modifications).
Frank

Presumably they have now learnt their lesson?
Next time they will gas them, shoot them, poison them, and generally use whatever extermination method works best to genocide the whole bleeding lot......and THEN pay for the bat survey which will find nothing......Job done!
Same problem with the great crested newt - which is classified as endangered yet seems to be encountered in every single garden pond everywhere when it comes to planning.
Solution - you must flatten the garden pond at all costs before you even discuss planning/extension/rebuilding. Once the council/objectors get wind of the fking newt your life will be hell.

 

[Flyfisher]

I once spoke with a builder who said he had worked on loads of old properties over a few decades and had never seen a bat in any of them.

Very nice chap, but I think he had something in his eye as he kept winking while recounting the tale. :wink:

 

[FamilyWiggs]

I wasn't joking about the cat. Nudge nudge wink wink. :wink: