Help To Fill A Deep Crack

[WhiteVanJack]

Hi,

In the hope that there are some experienced "deep crack" fillers on the forum I would be grateful for some advice on the following.

I have a concrete window cill with a crack running along the length of the top face. In parts this crack is around 4" deep lessening in depth towards the ends. I have cleaned it up and raked it out ready for filling, however, I will not be able to press the filler right down to the bottom due to the narrow width and irregular shape of the crack.

I had thought of using some expanding foam to get right to the bottom then cut the foam back a bit at the top and apply the top level of filler (Toupret Masonry Filler). Alternatively, could I sprinkle in some dry quick setting premix powder to get to the bottom of the crack then let it harden off by absorbing moisture, then, follow this up with the top level of filler?

On reading the data sheet for the Toupret Masonry filler it states it should not be applied onto soft or friable backgrounds so I am unsure if I can use it on top of the expanding foam unless there is a foam version that sets hard?

Once filled, the cill will be painted with masonry paint.

Any advice most appreciated.


Rgds
Jack

 

[roughcaster]

I've seen many concrete window cills with severe cracks running along the length. It's caused by the reinforcing bars rusting, within the concrete cill. Although you can do a makeshift job by cleaning/prepping, and putting in an external filler/cement, it'll only be a matter of time before the crack comes back. In the long run, although it costs a few bob more, it's better to replace the cill,,, depends what you're looking for really.

 

[WhiteVanJack]

Roughcaster,

Thanks for the reply.

At this stage I will settle for a repair of the existing cill. It is high up on the gable end and is the cill for a small window in the loft on the gable end wall.


Rgds
Jack

 

[jrplastering]

i was goin to say you could repair with this stuff
http://www.screwfix.com/prods/62007/Fixings/Injection-Fixing/R-KF2-380-for-Tarmac-Masonry.
weve use this for minor repairs from time to time never had any problems with it mate

 

[WhiteVanJack]

jrplastering,

Thanks for the reply, it is very interesting, I had not thought of using a fixing resin but I would certainly be able to get to the bottom of the crack with the applicator nozzle.

Would you be able to let me know if it can be applied using a standard metal frame mastic gun or is a special gun required to force the resin from the two chambers into the mixing nozzle? Also, how viscous is it, ie, will it slowly self level and flow into the nooks and crannies in the crack?

It certainly seems a good option and worth considering.


Rgds
Jack

 

[jrplastering]

haha plstring i was waiting to see how long it would be before someone replyd like that to be honest that was my first thought of summit to say aswell.
im not 100% sure bout the gun required for this brand of product the one weve used was a more expensive version supplied to us by a building company and did require a special gun but it was the tippy top of the range product. i woulkd ask who you buy it from bout the aplicator gun.
with reqards to your other questions the stuff can go in as deep as you wish it to i would squeeze it into the crack untill it comes out the top then use a gloved finger to push it right down to just below level that way it wil be as deep as it can go and leaves you enough room to fill over the top.
it is very strong stuff we use it to help stitch brick and block work together with a heli-bar kit but that is expensive bout £160 i think.
i dnt think you can go far wrong with the resin fix to be honest, the client or yourself will have to accept that at some point though you will have to replace the cill, but i believe this resin fix will give you the strongest and longest fix.

 

[roy c]

I would go with roughcasters reply ,do it once ,do it right!!

 

[Alastairreid]

I would go with roughcasters reply ,do it once ,do it right!!

Agree with Roy and R/C it wont last and you will spend as much on fancy fillers as you will a new cill....

 

[WhiteVanJack]

Thanks for all of your replies, they have been helpful.

If I opt for the new cill route I would need to get a quote for the supply and fit of the cill as I have no experience with this type of repair. Would a general builder be OK or is it a more specialised job requiring someone with more "stone" skills? If anyone could point me in the direction of the trade to approach for quotes I would be grateful.

The actual cill is surrounded by painted pebbledash which I presume would need to be cut back one inch all round the cill to prevent large chunks of the pebbledash falling off when the old cill is removed?

Going back to the resin repair, after "jrplastering" had pointed out the resin route, it occurred to me that to reinforce a resin repair I could drill some holes into the vertical face of the cill then use threaded stainless steel rods in the holes with resin. Hopefully, if I opt for the resin route this might give it a bit longer life? I checked the depth of the crack yesterday after some of the replies to the topic and at one point at its deepest it has gone all the way through the cill.

I do accept that the correct way is to replace the cill but I am pushed for time to get it all done and the pebbledash repaired and painted before the scaffolding comes down. If I go for the replace route I really need to get quotes as soon as possible to try to get it completed before the end of March.

It seems that there is a lot of expertise on the forum at filling deep cracks including some who are willing to help novices to see how it should be done correctly.


Rgds
Jack

 

[jrplastering]

oh this is how it is, is it boys haha gang up on jr .
i only mentioned the filling option as in a prevous post the OP had expressd he did not want to remove the cill.
given the choice its got to be remove and replace every day of the week.
you know what the saying is.
"a job worth doin, is a job worth doin............"




with filler haha jokes

 

[WhiteVanJack]

To be honest, it is a trade off for the method of repair. The cill is 30ft off the ground on the gable end wall near to the apex of the roof. If the cill was in a more prominent position and generally viewable and could be replaced in the next 2 weeks I would definitely opt for the replacement.

However, due to time constraints with the scaffolding coming down in a few weeks time and the cill then becoming inaccessible my original thoughts were that the quickest solution was a repair of the existing cill.

"jrplastering", thank you for the heads up on the resin option, you are quite right, I did ask for a method to achieve a repair. It is only after the other "deep crack fillers" pointed out that a crack always reopens that I started to consider the replacement.

I have no idea what the cost of a replacement cill with labour would be, it is approximately 2ft 6" long. Should I be getting a couple of quotes from general builders or is it a stonemason I should be asking for quotes for a replacement?



A deep crack that will always open up, perish the thought, thats a lot of work to keep it filled, a labour of love I suppose.


Rgds
Jack

 

[stevethespreader]

To be honest, it is a trade off for the method of repair. The cill is 30ft off the ground on the gable end wall near to the apex of the roof. If the cill was in a more prominent position and generally viewable and could be replaced in the next 2 weeks I would definitely opt for the replacement.

However, due to time constraints with the scaffolding coming down in a few weeks time and the cill then becoming inaccessible my original thoughts were that the quickest solution was a repair of the existing cill.

"jrplastering", thank you for the heads up on the resin option, you are quite right, I did ask for a method to achieve a repair. It is only after the other "deep crack fillers" pointed out that a crack always reopens that I started to consider the replacement.

I have no idea what the cost of a replacement cill with labour would be, it is approximately 2ft 6" long. Should I be getting a couple of quotes from general builders or is it a stonemason I should be asking for quotes for a replacement?



A deep crack that will always open up, perish the thought, thats a lot of work to keep it filled, a labour of love I suppose.


Rgds
Jack

jack take a look at this it looks easy http://www.diy-projects.co.uk/windows/replacing-a-cracked-concrete-window-sill/

 

[WhiteVanJack]

Steve,

Thx for the link.

Nice user name by the way, very appropriate for filling deep cracks.


Rgds
Jack

 

[stevethespreader]

Steve,

Thx for the link.

Nice user name by the way, very appropriate for filling deep cracks.


Rgdsa
Jack

so you going to have a go yourself jack?

 

[WhiteVanJack]

Steve,

I am still undecided about a replace or a repair. If I go for the repair I will do it myself. If I go for the replace I have no skills in that area and although it looks straightforward I would be a bit nervous about the work.

The choice may be forced by time into a repair as the scaffolding comes down in a few weeks time and I would need to have the cill replaced and the surrounding pebbledash repatched and painted by then The cill is not accessible even with ladders once the scaffolding is down.


Rgds
Jack