There were rats in the ceiling and now the room is filled with flies!

[Petrifiedofrats]

We are buying a property where rats were coming in via a disused drain up in to the ceiling of the extension. A part of the ceiling was taken down and a HUGE amount of rat droppings fell out from the insulation. This has been cleaned, re insulated & a rat flap put on the drain.

There are now an unbearable amount of flies in the room. Do we think this could be from the droppings falling in to the room? The ceiling has been re-plastered so if there were a dead rat in the ceiling I don’t see how they could still get in to the room after it has been plastered!

They could be cluster flies. Might have been hibernating in the loft and then disturbed when you did the work. Open the window and fly spray them. They should go pretty quickly. You might need to repeat for a few days.

I agree it could be cluster flies. Bit bigger than a house fly, might zoom around a bit then some of them will just drop dead. We used to get hundreds in the gap between window openers and frame every winter.

If not, my best bet would be they're from a rogue decomposing rat body somewhere rather than droppings, maybe eggs that were laid before it was sealed up and are now hatching with your heating on. If so, it's not a nice thought but the flies hatch and fly away and that's the end of it. Just keep dealing with them daily and it will end.

We had squirrels in between the ceiling and the floor of the loft conversion and when they died we had a terrible infestation of flies. Eventually it calmed down but it was awful

If it's a dead rat you'll get flies for a couple of weeks, if you can kill one and have a look at the size and colour you'll be able to tell if it's a cluster fly (large and dozy) or a bluebottle, which are what live on dead animals. A bluebottle infestation is a bit more disgusting but easier to deal with as cluster flies return each year and are hard to get rid of