Not sure if i have caused myself a problem

[piper191a]

Hi Guys

I have been trying to get a tradesman to fix a window where the putty has come loose on a 1st floor window sill (see attached picutre)

Eventually i gave up and managed to get up there to fix, trimmed and replaced the putty etc no problem.

I noticed there was a gap of about 1 cm on either the side of the sills - it thought it was pointing failure, it seemed big for silicone to bridge so i filled it with expanding foam and sanded it back

I then thought about thermal expansion, there is no longer a gap either side of the window sill.

Is this going to cause me a problem come summer? do i need to get a window guy out to fix my screw up?

One of the gaps i filled is visible on the attached

Thanks.

 

[AC Power]

No need to worry. While the thermal expansion of wood vs brick does differ, it is not enough to be concerned about. Expanding foam can enlarge and cause warping of wooden sills while it's drying, but if you've experienced no problems as of now, your fine. Good Job!

 

[piper191a]

Thanks, there hasnt been any warping as of yet, the sill is vinyl however- does that make a difference?

Cheers

 

[AC Power]

No, it ok as is.

Vinyl does expand (axially) when it is in LONG lengths (±5m), such as vinyl siding. In that case, the vinyl siding is nailed loosely to the wall through the pre-punched slots (not holes). This way, the vinyl has "wiggle room" to expand/contract with changing ambient temps.

While your window capping/construction will expand/contract, it's negligible.

 

[piper191a]

Thanks, i have been imagining all sorts (such as the pressure of the expanding foam cracking the surrounding mortar / bricks as it dries) because the gun fired out foam much more quickly than i expected, i was fishing it off the flat roof below the windowsill for half an hour :afterwards

Logically i know the expansion is not going to be strong enough to crack brick of course

Thanks again, i will forget about it now, really appreciate the reassurance