Repairing Windowboard

[curium]

I've removed the plaster on the bay-window wall and this has exposed the space under the window board.

Initially I was considering replacing the window board but this is beyond my skill-level and I haven't the cash for a skilled joiner after I pay for the wall to be plastered.

What's the best way to make good the window board? I can sand it back and paint it but I'm less sure on how to deal with the underside?

Presumably it would have been bedded on mortar originally but the original mortar has all crumbled (lime?). I've removed the biggest pieces of mortar and this has left a void. Should I slip in some dpc and then fill with expanding foam?

It looks like the board is attached to some pieces of timber which are jammed into the masonry.

Whats the best way to make good before the wall is plastered?

Cheers

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[opps]

Expanding foam works very well as a DPM. I would push in some plastic shims and then use expanding foam.

 

[foxhole]

Decent sander will remove all the crap on the underside.

 

[opps]

Decent sander will remove all the crap on the underside.

A sharp chisel will be faster if used before the sander.

 

[foxhole]

A sharp chisel will be faster if used before the sander.

I prefer belt sander ,takes down metal almost as quick as timber .

 

[opps]

I prefer belt sander ,takes down metal almost as quick as timber .

True but the combination of caulk and old paint is very likely to clog the belt quite quickly. It is also an unnatural angle to work at.

 

[Deleted member 174758]

Open coat belts and crepe belt cleaner anyone? OK, you probably would spend more time cleaning the belt than actually sanding, but less if you Nitromorsed or caustic soda softened the paint first, then scraped it before pulling out the big guns (the belt sander, lest anyone thinks I'm being rude). Out of interesr, @opps, what us the "safe and effective" way to remove old paint these days, now that Nitromors has gone all woke and heat guns are out in case there is lead in the paint? I thought it was sanding with a vacuum attached or nothing

 

[opps]

Open coat belts and crepe belt cleaner anyone? OK, you probably would spend more time cleaning the belt than actually sanding, but less if you Nitromorsed or caustic soda softened the paint first, then scraped it before pulling out the big guns (the belt sander, lest anyone thinks I'm being rude). Out of interesr, @opps, what us the "safe and effective" way to remove old paint these days, now that Nitromors has gone all woke and heat guns are out in case there is lead in the paint? I thought it was sanding with a vacuum attached or nothing

Heatguns are fine so long as you keep the temperature below 500 degrees C.

Lead - Controlling hazardous substances - Managing occupational health risks in construction

How to control the risks from lead, commonly used as a specialist material and present in older buildings.

www.hse.gov.uk

With regards to paint strippers, I still buy the methyl chloride strippers but I do domestic work rather than commercial. In theory, you can only buy them in 5L containers but there are people willing to sell it in 1L containers on ebay.

If I had to use compliant products then it would be the Peel Away range of products (the ones that you cover with a film whilst it works away).