Need to fill hole in wall!

[TheRunningMan]

I have a hole in an inside wall that needs to be filled ready for cavity wall insulation to be installed.

It's 13cm across and 10cm high at its longest points (See pic below)

What will be the best way to block it up?

Cheers folks, Crofty

View media item 40443

 

[BigRobCanUFixIt]

cement?

Or you could square it up an bit an use a brick and some cement?

Or square it up and plasterboard it.

Rob

 

[^woody^]

Or you could square it up an bit an use a brick and some cement?

Or cut a square brick to fit the round hole?

 

[MINDEX]

expanding foam and plaster

 

[joe-90]

expanding foam and plaster

And how are you going to hold it in?

 

[MINDEX]

And how are you going to hold it in? [/quote]

when expanding foam hard, dig out 1 cm of it and fill with plaster- difficult?
will hold with same strength as plasterboard

 

[joe-90]

You don't half talk some nonsense. You can't put foam in an open lateral hole - it runs out.

 

[stuart45]

You don't half talk some nonsense. You can't put foam in an open lateral hole - it runs out.

I wouldn't use foam for that repair either.
Get a couple of bricks, and some broken ones and build it using sand/cement mortar.
The whole job should take about 10 mins.

 

[DIYbuilder]

I like the expanding foam option, I've even seen people use expanding foam and lumps of stone, brick rather than messing with mortar especially when if the mortar is mixed to wet much of it can run into the cavity causing other possible issues.

 

[xdave]

You don't half talk some nonsense. You can't put foam in an open lateral hole - it runs out.

I have used it in the past for much larger holes without any problems. It is particularly useful when closing an unused service hole that might need to be reopened in the future so long as you remember where it was.

Ensure the hole is completely dust free, spray it with a water mister and build in from the outside towards the middle using a gun set to a minimal flow rate. Build it up in layers if it is more than 50mm deep after about 5 mins and spray between each layer. If it will be plastered over stop 15mm short of the finished surface and build up using a tough plaster like hardwall and skim to finish.

PU foam only slumps if it is applied too deeply in one go which causes it to hollow out. If used as per the instructions it should be fine. Never use the hand applied cans - they are all rubbish.

 

[WabbitPoo]

cement?

Not a useful suggestion, as OP might think cement can be used on its own.

 

[joe-90]

You don't half talk some nonsense. You can't put foam in an open lateral hole - it runs out.

I have used it in the past for much larger holes without any problems. It is particularly useful when closing an unused service hole that might need to be reopened in the future so long as you remember where it was.

Ensure the hole is completely dust free, spray it with a water mister and build in from the outside towards the middle using a gun set to a minimal flow rate. Build it up in layers if it is more than 50mm deep after about 5 mins and spray between each layer. If it will be plastered over stop 15mm short of the finished surface and build up using a tough plaster like hardwall and skim to finish.

PU foam only slumps if it is applied too deeply in one go which causes it to hollow out. If used as per the instructions it should be fine. Never use the hand applied cans - they are all rubbish.

So where do you suggest the DIYer gets the kit for just one hole?

 

[stuart45]

The problem with using foam on a large hole is that as the back expands it can bridge the cavity causing a potential damp problem.

 

[xdave]

So where do you suggest the DIYer gets the kit for just one hole?

Any DIY shed. Screwfix sell an adequate gun for £15, and the foam is £3.75 - about the same cost as a bag of sand, a bag of cement and a throwaway trowel.

The problem with using foam on a large hole is that as the back expands it can bridge the cavity causing a potential damp problem

If you use the correct grade foam and don't go greater than 50mm in one go (depth in any direction) you won't get over expansion into the cavity or proud of the face. The key is to set the flow to minimum and ensure the surfaces are damp or it will just expand in any direction it can. PU seeks water agressively for the first minute or so and you can use that characteristic to control it. If you don't provide enough water on the surfaces you are bonding to then it will just keep expanding until the reaction stops. If you've ever overfilled a hole and seen it burst out of its own skin and continue to expand then you've seen what a lack of water will do to it. Give it water and the bulk of the reaction is over within seconds.

However in the OPs case they are getting cavity wall insulation sprayed in, so damp bridging with foam will be the least of their worries...

 

[stuart45]

A bag of readymix mortar and a cheap pointing trowel is a lot cheaper than £18.75p.