How can I secure a mesh covering to this window opening?

[suzlala]

Hello,

In my under house storage area there is an opening (roughly 66cm x 82cm) like a window, but with no glass in it. The metal bars are cemented in, but the mesh you can see in the photo is just a loose piece that the previous owner attached using zip ties. The large apertures in the mesh and the way it is currently secured means there is no protection from pests. The area around the window on the inside is quite rough because the cement was not smoothed down. The house is on a slope, so on the other side of this window is soil, going up to the bottom of this window opening (I will dig this soil away so it sits at least 10-15cm below the hole). The house sits on sandstone, so is prone to moisture coming through the rock.

I would like to cover the window opening in some way so the storage area is protected from pests and vermin, but try to maintain some ventilation because of the sandstone.

I was thinking of using some kind of mesh, perhaps in a frame, but wasn't sure how I could attach this securely to the brick/cement around. Then seal up the edges using some silicone or sealant, especially where the mesh/frame can't quite sit flush to the wall because of the rough surface.

Would this stainless steel insect screen be suitable?

https://www.bunnings.com.au/syneco-810mm-x-2-05m-stainless-steel-insect-screen_p4110616

I'm worried this might not be strong enough to keep out mice/rats though, so should I have a layer of netting as well as the insect screen? Bunnings sells mouse mesh with an aperture of 6.5mm.

https://www.bunnings.com.au/jack-900mm-x-5m-6-5-x-6-5mm-mouse-mesh_p3040081

Is there a stainless steel alternative? I imagine it would be difficult to change out the mesh in a couple of years time, so I would prefer something which doesn't rust and has no need for maintenance.

How might I attach these securely to the wall?

Any advice would be appreciated! Thank you.

[EricL]

Hello @suzlala 

Thanks for sharing your question about your window opening. I suggest building a rectangular frame from 70 x 35mm Outdoor Framing H3 Treated Pine - 2.4m. You then attach the Syneco 810mm x 2.05m Stainless Steel Insect Screen using a staple gun. Once the screen is attached you can install the frame inside of your brick wall using Ramset 6 x 75mm Galvanised AnkaScrew Masonry Anchor. I recommend removing the uneven pieces of concrete on the wall with a hammer and chisel.

Let me call on our experienced members @Dave-1 and @Nailbag for their recommendations.

If you have any other questions we can help with, please let us know.

Eric

[Dave-1]

Good Evening @suzlala 

Now this is an interesting problem you have....

I went looking for a 5mm square mesh (stainless) and there are a few out there that would be suitable.

To get the edge of the window / opening smooth or to a workable level I propose using some Earl's 10kg Concremate Expanding Cement and making up some formwork to go around the edge of the window. I have used concrete screws into the existing brickwork to provide fastening points for the concretemate.  This is my project Concrete patio repair and it worked very well.

I used CUSTOMpine 16 x 1800 x 445mm E1L System 32 HD Shelving White Carcass Matt Particleboard Standard for the formwork.

Once you have done the edge tho in reality it may not be needed then you fix the 5mm stainless mesh to the existing grill work via 4 of these strips Metal Mate 20 x 1.6mm 1m Silver Aluminium Flat Bar - Silver 1m Id suggest that you us ethe strips like large washers. You drill through two of them plus the mesh. One vertical strip them mesh, then the existing grill and then another vertical strip. Bolt them all together on the frame so its like a squashed sandwich. The steel mesh should be stroung enough not to flex if pushed or you could add some more strips to re-enforce it.

Dave

[Nailbag]

Hi @suzlala 

I really like the idea of using that stainless screen product as it's obviously not going to rust. Personally I think to keep the project simply but effective since it's not really a visible opening. So, I would go-ahead with the mesh cut to the size of the existing metal frame as we might as well utilise what's already there. Be very careful of the cut sides as they will now be razor sharp. To help the installation process, I would use a basic silicone sealant applied to the outer frame of the current grate to press the mesh into and hold it in place. Then you could use cut to length aluminium flat strips that had pre-drilled 6mm holes to sandwich the mesh in-between. Fix the strips with self-drilling galvanised button headed screws.

This should provide a very strong and long lasting barrier for insects to rodents.

Nailbag

[suzlala]

Hello,

thank you everyone for the thoughtful responses.

@Nailbag do you mean drill the screws through the aluminium strips and mesh .... into the existing metal frame? ... or into the surrounding concrete and brick?

If you mean drill into the metal frame, how can I ensure the corners are strong and stay in place? Unfortunately the corners of the window opening are rounded, and there are only 6 points where the existing metal frame meets the wall (none of which are in the corners).

If you mean drill into the surrounding wall, do you know whether those screws can go into concrete/brick? It isn't clear in the description. How far from the edge would you advise drilling? I want to avoid drilling too close and blowing out a chunk of wall.

Thank you!

[Nailbag]

Apologies @suzlala looking more closely at the photo I can see the current metal frame doesn't next rent to the actual opening. So, in these case I would still keep it simple and fix 20mm square tubing to the existing frame as Close to the edge as possible with self drilling screws from the inside. Personally I wouldn't be worried that the current opening isn't perfectly square or that the tube frame isn't fixed square either. Just get the tube fixed as close to the opening as possible which is there main concern for rodent protection because nobody will see the framer in any case. Then sandwich the mesh in-between with those flat aluminium straps.

I am very much a visual project appealing person so I am confident that from the external side it will be visually appealing though not perfect. I don't believe this is a concern because of the position of the opening.

Nailbag