Drilling a hole for an AC vent through pebbledash?

[Sprogginz]

I'm not sure how this is constructed but by tapping the wall on the inside, it sounds very hollow.

Just wondering how you might, if possible, drill a hole to install an AC duct, without messing the up the pebbledash?
If it is possible I'd imagine you start drilling from the outside but what drill attachment would be needed since it's not solid block?

I might just end up sticking the vent out the window if it's too precarious.

Thanks very much.

 

[23vc]

Stitch drill it from outside (6mm ish masonry bit) but make sure you know where the studs are to avoid them. It’s a pebbledashed on render board/lath type stud wall. No masonry.

 

[23vc]

Might be EML (metal mesh) actually - that’d be more of a challenge. I’d try and make some exploratory holes from inside to get a better idea

 

[JohnD]

The house doesn't look all that old, it probably has plasterboard on the inside. Make a small hole where you want the vent to go and have a look at the construction. It is probably studwork. Seeing where the studs are will help you decide the vent position. If you have the energy you could improve it greatly by taking off the plasterboard, adding a breathable membrane and insulating it, perhaps adding some electrical sockets, then reboarding.

 

[Sprogginz]

Thanks for all your help, I really appreciate it.

On one side, I'm quite enthusiastic about this project.

On the other side, I'm scared of ruining the pebbledash if a large piece breaks off or weakens it. I don't know how pebbledash reacts to drilling a large whole.

With a heavy sigh I think I'll just stick to putting the duct out the window. Has anyone had any experience drilling holes in pebbledash?

Thanks again.

 

[^woody^]

Id' be inclined to use a 4" grinder and carefully sculpt the round hole. This will prevent the rattle you will get from drilling.

But, if that is a timber frame wall, the issue will be supporting the area around the hole afterwards.

Also think about how to flash around the hole and pipe afterwards

 

[Sprogginz]

Not sure if I should've started another thread for this but with the downstairs bay window, there is a vent already there but it looks like it's been blocked with a brick. There is no longer a vent on the inside but just plaster.

I'm assuming I can use this one but what was the purpose of the brick? Could it have been used as a backing for the plastering? It seems to have been partially cemented in. Is this just a case of chipping away at the cement and then drilling a pilot hol

Thanks again.

 

[foxhole]

Just take a hammer to inside and remove brick .

 

[Harry Bloomfield]

I'm assuming I can use this one but what was the purpose of the brick? Could it have been used as a backing for the plastering? It seems to have been partially cemented in. Is this just a case of chipping away at the cement and then drilling a pilot hol

It looks as if someone has been keen to simply block the hole up, so has cemented a brick in, to close it off. If you know where it is on the inside, you could simply chip the plaster away to reveal it. If not, use a long masonry drill, drilling carefully from the outside, through the softer cement, to help you find it on the inside.

 

[mrrusty]

Probably a gas fire vent that's no longer needed. Yes, just open it up and use it.

 

[Sprogginz]

Continuing the saga, I've dropped making a hole in the pebbledash upstairs for now. Instead I need to make the hole of the old vent downstairs bigger. As you should see in the photo, I already had a couple of rasps which I tried.

They worked okay around the edges but not well grinding down the innards which I need to do for about 35mm. Other than using a hammer and chisel, is there a quicker and more effective way?

Also and once done, what would you recommend to replaster the area? Is there an instant or easy mix that would do the job? I'm looking online and there's plenty of fillers or repairers but I'm not sure if they're good for this size.

Thanks very much and hope you can help.

 

[JohnD]

If you have a core drill, to enlarge an existing hole you can fix a piece if timber across the other side with a pilot hole to locate the central drill.

You normally work from the outside inward, to avoid unsightly scabs as you break through.

Plasterers joint cement is very handy for patching. They use it on plasterboard. You can buy it in ready mixed tubs, it is a bit expensive but you don't need much. Keep the lid on tightly.

Jointing Compounds | Plaster & Plasterboard | Wickes.co.uk

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I've used the stuff with the yellow lid.

 

[Sprogginz]

Thanks for the joint/cement info, that looks like the ticket! It was my own stupid fault for making such a large mess of the wall.

Unfortunately I don't have a core drill bit. I think the one I need is about £60 and I only want to go in about 35mm for the AC's flange to fit in.
Thanks again.

 

[aveatry]

For the bedroom vent make a board that fits the open window space and put a hole into that. That s what I have done - I am assuming it is a portable air-conditioning unit.
I made one out of 4mm mdf for the window that when opened it replaces the window and is held in-place by cheap security turns o the inside

 

[Ivor Windybottom]

With a heavy sigh I think I'll just stick to putting the duct out the window. Has anyone had any experience drilling holes in pebbledash?

Thanks again.

Definitely put it out of the window. I'm assuming it's a portable air conditioner, it's not intended to be built in anyway. They're very inefficient, as they extract air so inevitably warm air will be drawn in elsewhere, usually through the open window or an internal door. Good for ventilation, not good for trying to stay cool.

If you want installed air con in your bedroom then buy a proper system. DIY options are available. This puts the noisy compressor outside, the inside unit won't be any noisier than a fan, as that's essentially all it is. The holes needed are much smaller, as liquid refrigerant is exchanged between the two units, not massive volumes of air.

But you need to be considerate of neighbours with air con. You'll be making noise at the exact same time your neighbours have their windows open. It's probably allowed in a terraced house but really it's not at all neighbourly to install one. A heat pump heating system makes a similar level of noise, but is used in the winter when most windows are closed.