How can one stop these cracks

[platforminc]

Hi All.

I just had an extension finished back in April this year, all of a sudden in the last 2 months I am seeing cracks appearing all over the place. The extension is a side and rear extension, the side extension is a timber frame building much like a loft, and the rear extension is brick.

Works passed by local authority building control.

I do get the fact that buildings move, but I would like to ask these questions because of next time, what could have been done during construction to minimise/reduce these cracks.

Things like, for example doubling up on the number of lateral restraints, so where it ought to be 10, can one use say 20 ? Will these reduce the effect of these cracks, could it also be due to weather fluctuations, the timber was swollen in winter when most of the construction happened, and now its summer, timber dried. I don't know, I am just coming up with my theories.

Does this also happen in brick built extensions ? I say this as I do not like the disruption decorating causes, you think once you have painted a house once, the last thing you want to be doing is patching everywhere with cracks.

 

[^woody^]

You won't stop them. Tiles should have a flexible mastic joint at junctions, not grout.

 

[platforminc]

Right.
What if they don't have it in the required colour, can Mastic be applied first and grout to finish?

 

[^woody^]

No. It should be a flexible joint.

 

[platforminc]

Excuse my ignorance, I just search for flexible mastic and I was getting all sorts of results, can you please post links of the required product please.

What should also be done in cases where the grout has not cracked ?

Thanks.

 

[CJRatch]

Have a search for Mapei silicone it comes it many colours to match grout.

 

[platforminc]

Nice, Mastic is just another name for silicone sealant.
One other issue, the crack has not appeared from top to bottom and also not across all the 4 corners, is it better to force the crack or remove the grout and then seal with silicone (how can one do this)
OR
wait till the cracks appear (I don't know when this will happen) and unless I want to be buying silicone all the time, I had rather apply once and forget about it.

 

[JohnD]

Mastic is just another name for silicone sealant.

No it isn't.

You might use it that way, but ancient greeks had chewing gum made from the sap of a Mastic tree. It became a very useful flexible sealant, sold under that name, and is still widely exported, but expensive. It is not made of silicone, and silicone does not contain mastic.

cf. "mastication" which means "chewing"

 

[platforminc]

Ahh.
What should I do about the rest of the grouting which has not cracked?

 

[CJRatch]

Just silicone over the top. If the grout cracks in the future the silicone will be flexible enough to still hide the cracks.