How deep into PIR will a mouse gnaw?

[Radian]

About 30mm by the looks of this hole:

 

I just cut out a plasterboard panel to access the eaves of our garage extension upstairs room to establish a cable run for our solar PV installation next week. Good to see the builder didn't tape the PIR to the wall plate and rafters 🙄 Nor did they extend the PIR between the bottom chord and the timber that closes the top of the intermediate cavity wall below.

 

Anyway, a mouse has been running around in the floor space and has had a go at making an exit tunnel to the soffit. He shouldn't have given up - he only had another 120mm to go 😂

[ProDave]

Airtight house builders will tell you a "satisfactory" air test, is when after 5 years, not a single mouse has found a hole big enough to enter and get into the house.

[Nickfromwales]

All you have to do is imagine yourself as the mouse.

Where Mickey can invade, rodent barrier. Simples.  You can keep the little blighters out, but it requires effort an attention to detail.

 

Same ethos for airtightness, where you study where a ‘molecule of air’ would travel to infiltrate your airtightness measures. It’s enough to make you lose a day just thinking about it, but try explaining this to a builder and he will have you certified. 

 

“They” just don’t get it…. I do try educating, but it’s a bloody uphill struggle. 

[Triassic]

Don't forget flying things trying to eat their way in. Had a wasps nest under the eaves this year. They buggered  off recently, so went up to pull the nest out and block the hole up, to find they’er chewed through the exterior timber frame membrane and the OSB.

[Radian]

I think it got in the floor before the building work was finished (found a few droppings when putting in some pipework) but there are a few places I can think of where PIR will be the only barrier and as it's now been demonstrated to me that they can nibble through it, I don't think I stand a chance of keeping them out now. Not now they know how cosy it is in the interstitial regions.

[ProDave]

At our old house every autumn (harvest time when they get driven out of the fields by the big lawnmower) they would get into our loft.  They were able to climb the outside wall, roughcast render, think "mouse climbing wall" and enter through the eaves vents or soffit vents.  You can't block those up to stop the mice.  Then you would hear them scurrying around under the loft insulation.  We used to just permanently keep rat poison in a tray to feed them so they did not last long.

 

That is why I am so glad we chose a warm roof this time and why I thoroughly recommend a warm roof vs a cold roof.  No need to provide mouse sized ventilation openings.

 

The only ones that got inside the old house entered via the cat flap in the mouth of the cat. occasionally one would escape the cat still alive and take up residence under the kitchen units.

[Radian]

27 minutes ago, ProDave said:

That is why I am so glad we chose a warm roof this time and why I thoroughly recommend a warm roof vs a cold roof.  No need to provide mouse sized ventilation openings.

 

There are some discrete eaves vents that sit on top of the fascia, we have those to ventilate our house (cold) roofs. These have a fine-pitched insect grille that no mouse would get through. But I was just wondering about this wonkeedonkee description of them here :

 

 

Use larger ones for warm roofs? What are they talking about?

 

Our new garage extension has a cold roof but a breathable membrane so the 50mm air gap between the insulation and membrane apparently makes it unnecessary to have any additional vent openings. The foil backed plasterboard inside is meant to control vapor getting to the insulation layer but will be full of holes for electrical stuff. 

 

Next stop for the vapor; the the un-taped insulation. On the bright side, at least the vapor has an exit route, on its way past the cold outside air that's replacing it 😭

[ToughButterCup]

Mice? Mice?

Try  our rats. Since we live next to what has recently become a pig-farm, we have some right cocky fewkers. 

Once they'd eaten through the rodent mesh, they were into our roof space (all 80mm of it) like , well, rats up a drain.

 

Here's the kicker : they continued to gnaw in the roof space immediately above our bed head.  Sciffle scuffle scuffle. Sleep impossible.

As luck would have it, when the rats struck, I hadn't taken the scaffolding down.

 

So - in my Jim-Jams at 10:30 of a freezing evening - flip-flops frozen to my feet, I'm up the scaff ladder like a homesick angel.

 

Pitch black outside. Nuts somewhere in my throat

Grab a spare scaff pole which was lying on the boards. 

 

Using that pole, bang really hard on the barge board - hard. Hard enough to warm me up a bit. I wuz furious.

 

SWMBO shouts from inside -

 

"What da Fekkety Fek's that - - - sweetheart? "  ( a bit late that endearment - sweetheart)

"Lesser-spotted pole-rat darlin"

"Well it's still nibblin' "

 

Bollerks; Bang very hard, start to slip on the frozen scaff boarding.

 

From up there, I look down at the lane next to our house: pitch black except for a red-flashing set of lights and a dim haze reflected from a hi-viz jacket . - No street lights -

Ooooops: my near neighbour walking her dog. It had stopped to look at the eejit up a scaff this late of an evening.

 

"Hi Ian, howzit goin' ? Cold up there is it? "

"Can you tell from down there [.... name redacted ...] . I'm amazed."

 

Only then did I notice that my legs and withers  (but not my rippling-muscled torso) were illuminated by the light from our bedroom window. 

Its amazing what tremendous night-vision women  have. I thought it was cold enough for it to be invisible.

But no, apparently .

 

Anyway, local Rat Man came and sorted it all out. And I ordered a new night-sight for my gun. 

 

Worthy opponents, rats. Worthy opponents.

 

 

 

 

[markocosic]

14 hours ago, Triassic said:

...to find they’er chewed through the exterior timber frame membrane and the OSB.

 

Though the OSB too? 😮

 

There's no stopping the things 😕

[ToughButterCup]

17 hours ago, markocosic said:

Though the OSB too? 😮

 

Their teeth never stop growing. They have to gnaw. They'll gnaw through thin metal mesh.

[saveasteading]

Once dead in the attic, a mouse stinks for a day and a rat for a week. I assume there are lots of skeletons under the fibreglass quilt.

[Radian]

4 minutes ago, saveasteading said:

Once dead in the attic, a mouse stinks for a day and a rat for a week. I assume there are lots of skeletons under the fibreglass quilt.

That's what I was thinking. I'm dreading going back up into our main house attic to finish adding to the insulation for fear of the biological horrors that await. And we were setting humane traps last year for this very reason, but it doesn't stop 'em dying of old age!

[markocosic]

At least a week for a rat IME. They take an age to dry out and stop stinking. 😕

[ToughButterCup]

Unlucky @markocosic : very often rats regard their dead brethren as lunch. Waste not want not.