Garden Room Workshop Extra | How To Stop Mice Under Your Floor!

A quick video on how my floor insulation is faring now that some time has passed. I also investigate the options to stop mice and other pests nibbling the insulation or getting under the floor altogether.

All floor designs courtesy of Paul Hollingsworth 👍👏

[AliDymock]

Just a short one today. Are there any preventative measures I didn't think of?

[Tom-Lahaye]

I can confirm that rock wool or glass fibre insulation make great nesting material, especially the non bound type you can buy on rolls, often with a paper casing around it.
I just finished demolishing some ceilings from under the flat roof of my house, and had never experienced a shower of mouse and rat faeces like when I started to rip the insulation out.
The insulation was done wrong anyway, the roll was tacked with a nail every foot or so, no taping and no vapour barrier installed.
Result is that the underside of the plywood roof boards are damp and mouldy, but luckily not rotted yet, apart from a small older looking piece.
On the insulation however I found small rotted pieces of chip board, so apparently this had been used as roof boards before, and the combination of the chip board, insulation and no vapour barrier had apparently disastrous effects in a very short time.
But DIY people in the 1970s and 80s when this was done didn't have access to all the knowledge we have now with internet, so mistakes were very commonly made.
There is a new roof membrane and warm roof insulation going up.
On the garage connected with the house straw cement boards have been used and these are deteriorating, new boards will be laid on this part anyway, so any less than perfect boards on the house part will be replaced as well, some boards aren't rot but have sagged a bit between the joists and this promotes pooling of water on the roof.

[chrisfreestone]

Great vid, to the point and informative (and the answer I wanted!). Thanks for making.

[boyblunder]

Rats taking up residence under my old summerhouse has been a big problem, I’ll need to deal with that on the new project that’s in planning now. Great stuff 👍

[hitmon]

Great video. Love your use of Sketchup to clearly show what your saying. Would you consider making a quick tutorial on how you use it yourself and how you built your models for the garden room? i.e. NOT a total beginners guide. Thanks!

[craigwelsh]

For my log cabin foundation i stapled chicken wire (4 layers thick) to the perimeter double beams and hammered weed control spikes through it into the weed control to keep it in place. Gravel a few cm deep is in a channel around the building uo against the chicken wire so if anything is burrowing under i should know from that.

I do have foxes, squirrels and mice in the garden and not spotted anything attempting anything yet thiugh the main floor has only been down a month.

Incidentally i did find earwigs liked to burrow a little into the pir while i had it stacked in the garden awaiting cutting etc. They didnt get far in before dying though! I believe a lot of them hitched a ride to the UK from holland with my cabin.

[captainbuggernut]

Apparently mice and rats don't like the thin foil that covers the insulation. They cut their mouths chewing on it. Or so one manufacturer claims. Personally I went with vented membrane, £34 for 50 metres and mesh which I already had for fencing. 6mm holes and £50 for 15 metres from Amazon. I put that over the membrane and stapled it round the floor. Stood on some cheap, green treated bearers which were £4 for 3.6 metres from Travis Perkins.

[colinwhite]

I went for a chicken wire and thick gauge mesh. I stapled mesh (which I reclaimed from a municipal tennis court refurbishment) and then folded it flat for 2 ' out from the building. This was covered with gravel, to prevent foxes digging under.

[rdownmakeITbetter]

As I understand it mice and rodents are attracted to thermoplastic such as expanded polystyrene which they can actually digest. However, most insulation products these days are thermoset plastics (for obvious fire resistant properties) so do not appeal in the same way.

[Jarul]

Good video 👍🏼, it's the reason I plan to put in a perimeter wall

[joeharman]

Just in the process of planning a garden office build and having the conundrum of concrete slab or concrete block foundations. Now leaning towards the former given this video even with the extra cost. May I ask what you would opt for if you was to build another garden office?

[MagicMarvin]

I had squirrels and mice ruin my board insulation. Don't think they would eat it but if they can they dig into it. as long as its not exposed I think it should be fine. Most was fine but parts where it fell slightly or was pulled out by them they tunnelled into it.

[TrotterG]

Would the OSB underneath present any risk of trapping moisture and causing issues?

[benboy]

Hi Ali, thanks for all the videos you've done I'm just a floor level now. I'm going to leave the underside exposed exactly how you have.

From a few other videos I've seen, it's been suggested to allow a gap for both cats and foxes to get under to be a natural pest control measure. Makes sense to me. If your garden room is to be used on a regular basis foxes are unlikely to create a den under it 👍

[mohammadsiddiqui]

Good morning, what size timber you used for the floor. 150x50? Thank you

[stevet]

Ali I jest wanted ask one more question, I have decided to concrete the base but wanted to put a damp proof membrane in and I have looked on the web and not found a reasonable answer. Do you know if it’s best to put the damp proof membrane concrete and Typ 1 or over the concrete. Thanks for being there.👍

[hyseb]

Damn man, that ending is a helluva cliffhanger!

[lukedogwalker]

I'm a fan of a perimeter foundation, partly for load bearing, and partly for keeping the rats out. They like to burrow under supports, and I don't want them undermining a plinth! I may use plinths inside the perimeter, or just subdivide the area with extensions of the perimeter, which should ensure I get a very solid floor.

Also, at one end of the building I get a lot of leaves and other material blowing in, and don't want ritting masses liling up underneath the floor. The perimeter should keep that out.

[LluisTheWoodWorker]

Nice info! I have a brown rat under my workshop, quite big about 40cm in length including the tail. I really don't know too much what to do I have tried poison but it hasn't even touched it. I can hear it chewing the insulation or joist... quite worried but i really don't know what to do! Thanks for the vid love them!

[Benzknees]

Mice got below my house floor despite air bricks being the only entry point. It’s amazing what space they can squeeze through. Nevertheless they don’t appear to have ever chewed thru my electric cables (I hope!), which you’d think would be an obvious target.