Masticing Joints

[Shutpa]

Surveyor tells me that the spaces between the metal strips on the outside walls require to be remasticated (is that a word?) and I would be grateful for advice on a good product to use.

 

[RedHerring2]

Teeth are used for masticating.

Other than that, I think more info' is needed. I was going to say "a bit more info'" but on what you've said so far, I think a lot more info' is needed.

 

[Shutpa]

I think more info' is needed.

Hi RH2 and thank you for your reply. The only info I can give is that some 10 years ago, we extended, and where the 'old' meets the 'new', there are vertical galvanised metal strips which have been filled with mastic which has since perished and cracked. Likewise, on the gable wall of the extension, there are a further 2 galvanised separators in which the mastic has cracked and therefore do not seal the gap as intended. I simply want some well informed member to recommend a mastic to fill the join after I have removed the old.

 

[freddiemercurystwin]

Your local merchants will sort you out, get a colour to suit the walls eg http://www.tool-net.co.uk/p-324647/everflex-115-gp-building-mastic-brown-310ml.html

 

[Shutpa]

Cheers Freddy, that's exactly the kind of info I needed.

 

[noseall]

I have not come across a building inspector or an architect that insists that this particular connection needs to be mastic filled/sealed.

Every single extension i have built (quite a few) has had this joint filled conventionally, i.e. with a mortar joint. We have encountered no problems as yet.

And it looks a whole lot neater.

 

[^woody^]

If you are going to mastic, use a polysulphide mastic or Silicone and not an acrylic mastic

I notice that the product FMT linked to only as a life expectancy of 10 years, which is not a lot. Typical PS or Silicone will have a life expectancy of 25 years and wont cost any more

But as noseall say, this joint can just be pointed up - after 10 years this extension should be reasonably settled

 

[Shutpa]

I have not come across a building inspector or an architect that insists that this particular connection needs to be mastic filled/sealed.

Every single extension i have built (quite a few) has had this joint filled conventionally, i.e. with a mortar joint. We have encountered no problems as yet.

And it looks a whole lot neater.

Hi and thanks for your reply. I think the guy only suggested mastic because that was what was in place originally. That said, from a personal point of view, I would have great difficulty filling the narrow gaps with mortar being inexperienced in this field. I may however, give a small area a try and see what happens.

 

[Shutpa]

Typical PS or Silicone will have a life expectancy of 25 years and wont cost any more

Cheers for the reply Woody. If I do end up using mastic, I will certainly take your advice.

Edit: Just had another look at the existing mastic and the surveyor is right regarding the state of it. It's all cracked and when I picked out a small loose part, other pieces just slid down the groove.

 

[noseall]

I have not come across a building inspector or an architect that insists that this particular connection needs to be mastic filled/sealed.

Every single extension i have built (quite a few) has had this joint filled conventionally, i.e. with a mortar joint. We have encountered no problems as yet.

And it looks a whole lot neater.

Hi and thanks for your reply. I think the guy only suggested mastic because that was what was in place originally. That said, from a personal point of view, I would have great difficulty filling the narrow gaps with mortar being inexperienced in this field. I may however, give a small area a try and see what happens.

My post was describing actually building a mortar joint as you go and not particularly retrospectively filling the joint with mortar.

If, as you say, the joint is tight, then a poly-sulphide mastic gunned in is the way to go.

 

[Shutpa]

If, as you say, the joint is tight, then a poly-sulphide mastic gunned in is the way to go.............

..................and I have decided that "poly-sulphide mastic gunned" is the way that I will go. Thanks for your advice and thanks also to the others who contributed to the thread.