Filling a major gap.

so buy a tube of decorators filler

gaps under slabs on the piss? Lift em and use sand. Sand/cement will also work.

NT

some places).

Eh?

Slabs are level it is just that the top of the slabs are uneven (not as bad as riven ones though) so the greenhouse base is not flush all around want to fill this gap .

I'm confused about the size of the gap the title says "major" which to me is anything over about 3/8" wide and deeper than 1/2". But the message just refers to a gap on leveled slabs that aren't riven, so only 1/4" max?

Either way just get a tube of suitably coloured exterior grade silicone and use that. The gap is likely to be deep so ram something(*) in to it to a depth of 1/4" or so and fill against that.

(*) News paper, strip of foam plastic, doesn't really matter. It's only to stop the filler going too deep on application.

Mea culpa, panicked a bit when I first sort of realised there was a gap to fill rather than just me running a small bead of sealer , around the base (to keep insects out).It's a bit dark and rainy out there to actually measure but I would say it is closer to ¼"~½" but it seems major to me. Think I will go the sealer rather than the mortar route (exterior filler is only about 90p~£1:00 a tube [380ml]). Does not need any mechanical strength, aluminium on top concrete slabs below so no abrasion resistance required. Can water (once sealant has set) affect the sealer chemicaly, any tube I have seen says don't apply in standing water but there is no similar caveat for once the sealer has set.

Acrylic sealers take quite a long time to cure, but I would have thought that that shouldn't matter for this application. It's difficult anyway to keep insects out, so perfection isn't needed.

I'm pretty sure I have seen empty tubes for sale somewhere....can't remember where though. Possibly a decorating supplies shop.

I also believe that Lidl had some trigger operated "caulking" guns a while back that you could fill with your own stuff.

I was half wondering why you wanted to seal it anyway, keeping bugs out =

makes sense. At least they won't beable to crawl in and out quite so easily, they will still get in though.

A sealant will also be flexable and give with the thermal expansion contraction of the ali relative to the slabs. You'll probably need more =

thane one tube. Buy more than you think and take back any unused, unopen= ed ones for a refund.

Surafces need to be clean, dry and dust free. Even damp will affect the =

adhesion of the selant.

Ooops, rains a lot this time of year, I would obviously wait until there were no pools of water but how dry do you feel the slabs have to be?

I'd pick something that isnt affected by sitting in water, which rules a lot of sealants out. Silicone would work, its not the most robust stuff about, but a large bead of it should stop insects.

NT

To keep insects out it seems a bit of a waste of time, plenty will make their way in. Though it's probably worth it to keep out drafts if you a re going to heat it.

I would use a hot air gun on the area to be sealed to dry it out first.

That is what I'd do, takes a surprisingly long time to dry even a small bit of concrete as well.

TBH the sealing it against insects is pretty much the wife's idea I basicaly have no problem with insects getting in (indeed I would prefer some type of "weep" holes; may do that yet and not bother to tell the wife) . As for heating I think it is only going to be one of the "fill once a fortnight" parrafin jobs to just take the edge off the cold

I'd just wedge each side up a little, stuff some strips of closed cell foam like from pipe lagging in there, then drop it back down.

cheers, Pete.

My greenhouse stands on an aluminium base on slabs, and when I built it a friend ran some bog-standard mastic round the bottom. I haven't seen a bug or a slug in there in the eight years it's been up.

Base is screwed (via brackets) to the slabs so levering up the G/house was/is not an option.

Did the aplying filler yesterday. Over night it rained, had a look at it this morning and everything was white, the rain had dissolved some of the filler, luckily I had only done one side as a bit of a test, so after flapping a bit wiped up the "white water" and packed sand and cement (wet) into the gap using my fingers and a thin piece of wood. Anyone know if "bloom" on slabs remains unsightly or does it fade away or do you stop noticing? This bloom is not a real problem just son paid a fortune (for him; he recieved cash for birthdays and Christmases [he is at that awkward age too old for toys too young to appreciate clothes]) for this greenhouse so I want to do as good a job as possible.

Hands are now in ****state, do not recommend getting mortar on bare skin. :)

I was going to do the bead of filler to seal but due to the surface finish of the slabs had to prop up the corners of the base of the greenhouse (to level it) so there was a definite gap around most of the base rather than an easily sealed slab/base interface so it was advice on filling this gap rather than sealing the base.

The seal will keep out snails, slaters (woodlice), slugs, insects of that type; can't imagine any seal (I could do)that would keep out ants V-small spiders etc>

Did the aplying filler/caulk yesterday. Over night it rained, had a look at it this morning and everything was white, the rain had dissolved some of the filler (the filler takes a l o n g time to set), luckily I had only done one side as a bit of a test, so after flapping a bit wiped up the "white water" and packed sand and cement (wet) into the gap using my fingers and a thin piece of wood (hands and knees job, knees are now V-sore. Was only going to do the three remaining sides but the sealant left a very noticable white line so covered this with a skim of mortar Anyone know if "bloom" on slabs remains unsightly or does it fade away or do you stop noticing? This bloom is not a real problem just son paid a fortune (for him; he recieved cash for birthdays and Christmases [he is at that awkward age too old for toys too young to appreciate clothes]) for this greenhouse so I want to do as good a job as possible.

Hands are now in ****state, I do not recommend getting mortar on bare skin. :)

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I'd have used an old icing bag, with a large nozzle, or a poly bag with the corner snipped off... I can recommend Avon Intensive Care hand cream... ;-))

Cleaned out a filler tube and filled it with mortar but it was almost impossible to get the mortar to come out,so that idea was binned. I imagined if I'd put the mortar in a bag that the bag would burst and the mortar would "splurge" everywhere, so that idea was binned . Didn't have a piping bag and I didn't want to leave the filling to go to the shops and get one, going to the shops is a non trivial exercise as we live in a wee village (Balerno) outside of a city (Edinburgh), so that idea was binned . So that was me reduced to crawling about on my knees pokeing mortar into a gap with my fingers.

I am using "Nulon expert hand care with aloe vera", must admit I feel a complete jessy using hand cream, but the skin on my hands really is in