Re caulking advice

Little Dorrit

Little Dorrit

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I wanted some advice please on some deck re caulking I am planning to do later this year.

After reading quite a lot of different articles including trawling this forum for advice I have managed to achieve a good result but at the expense of considerable time. I "practiced" last year on a small area and was pleased with the process, methods, tools and materials I had been advised to use.

My only frustration was that some of the existing caulking was stuck fast and difficult to remove. In fact it was so well adhered my instinct was that it was probably ok to leave but all the advice was to remove all trace of old caulking and re caulk on a perfectly clean joint - so that is what I did.

Is this level of perfection really necessary taking into account it takes a considerable amount of time and presents an added risk of opening up joints (a definite no-no)?

I am planning to use DS Deck Sealant which is described as a one-part neutral cure system, a thixotropic material which does not sag during cure. No priming is required but a thin strip of tape on the base of the is recommended.
 
If you don't remove all the remaining caulking, you'll be trying to apply the fresh up to an obstruction with the risk of a void and subsequent leak. In adition you'll have a section older than your new stuff which will probably fail first and force you to repeat the whole exercise! The idea is to maintain the integrity of the job as a whole, the caulking being liquid whilst worked, allowing it to flow into the joint and curing without flaws.

I've never caulked a deck, but everything I've read suggests that the safest method for relatively unskilled hands to remove the old is a reciprocating tool ( the type which pretty much vibrate the blade). Like so many things that have been re-invented for the DIY market I recall an old East German, carvel Folkboat in our yard which needed complete re-caulking. We chatted about the possibility of splining it as a one-time only job as the owner rightly feared getting slap happy as the job of chiselling out the joints wore on. It transpired that his wife was a hospital nurse, so he borrowed a cutter designed for removing plaster casts (a small reciprocating circular saw) - it worked a treat, and the job was done in two days!

Rob.
 
I've used a multi tool with a hook fitting for removing the old caulk. They're sold by Fein in a number of widths and make the task of removing caulk simple and fast. Don't use the tool on a high speed setting or you'll remove large lumps of teaks as well.....
If your decking is not screwed down and simply stuck to the underlying grp, then you don't need a release tape at the bottom of the groove. The release tape is there to allow planks to move somewhat in relation to one another on teak decks that form part of the weather proofing of the deck.
I run a line of masking tape down each side of the groove, fill the groove with caulk and then smooth it down with a scraper. That helps expose any 'holidays' in the caulk which can then be filled. I wait until the caulk has hardened to a reasonably tacky state and the carefully remove the tape. Leaving it too long make it difficult to get all the tape out...... I then let it fully harden for a week or so before lightly sanding the caulk and teak to produce a nice even finish and clean teak.
Now, this is fine for simple 'cosmetic' teak decking but I have no doubt that someone will be along to tell you how to do it if the decking is screwed in place or if it is not laid on grp but onto a wooden substrate.
 
Thanks for the advice. I'm panning to buy a multitool and some of the Fein cutting blades (probably the 3mm and 4mm blades). Unfortunately the Lidle multitool which I saw advertised is not currently available but I am not sure if they take the Fein cutting blades? However I have read somewhere on this forum that the Silverline range of tools from Toolstation will accept them.

I agree that there are quite a few different approaches to take in getting the job done I have previously used a homemade bend screwdriver suitably sharpened but as I said below it was quite time consuming as much of the old caulking is stuck very well.
 
paella said:
Thanks for the advice. I'm panning to buy a multitool and some of the Fein cutting blades (probably the 3mm and 4mm blades). Unfortunately the Lidle multitool which I saw advertised is not currently available but I am not sure if they take the Fein cutting blades? However I have read somewhere on this forum that the Silverline range of tools from Toolstation will accept them.

I agree that there are quite a few different approaches to take in getting the job done I have previously used a homemade bend screwdriver suitably sharpened but as I said below it was quite time consuming as much of the old caulking is stuck very well.
Click to expand...

B&Q own brand McAllister do a good multitool at about £48. The tool is one of the few to include a set of adapters to fit any of the various blade types. It's what I have and is a good compromise between quality and price.
 
I used a laminate router with a length of timber screwed into the adjoining groove to redo all my decks.They were however straight lines though.Perfect depth and width,should be 6mm deep/wide from memory.Couldnt get on with the Fein,too slow,fiddly and with risk of wobbly lines/cutting into the teak unless you have an extremely steady hand.Did use the Fein along with a chisel to do around the toe rails and coachroof which were curved/followed the lines of the boat.
You do need clean dust free grooves,as with everything preparation is key and yes it does take along time.Did mine over 2winters,did it in two sections,Bow and side decks followed by steps and raised rear deck.
Don't forget the plugs covering the screws,if the deck needs caulking then it's odds on there's not a lot of wood plug left covering the screw head.
Good luck,it is a slow,methodical process but when done immensely satisfying.Well it was for me:)
 
I think I read something on an earlier thread regarding this approach. It may even have been posted by your good self! My decks are not laid uniformly in straight lines so I think I'm going to try a get a mutitool, they are glued rather than screwed which helps too. I'm quite dexterous having spent quite a few years in kitchen so feel confident I can get a good results with a multitool. One thing that hasn't been mentioned in any previous posts regarding using multitool a is that a proper Fein (as opposed to other makes) is quite smooth running due to the way the mechanism works and if I'm right this could make a big difference; what you don't want is lots of vibration. To b honest this is a little bit of speculation on my part but since a new Fein can be picked up for just over £100 it seems a small price to pay to get a good job done properly.
 
paella said:
My only frustration was that some of the existing caulking was stuck fast and difficult to remove. In fact it was so well adhered my instinct was that it was probably ok to leave but all the advice was to remove all trace of old caulking and re caulk on a perfectly clean joint - so that is what I did.

Is this level of perfection really necessary taking into account it takes a considerable amount of time and presents an added risk of opening up joints (a definite no-no)?

I am planning to use DS Deck Sealant which is described as a one-part neutral cure system, a thixotropic material which does not sag during cure. No priming is required but a thin strip of tape on the base of the is recommended.
Click to expand...

There's no easy way to re-caulk; it's a long and arduous process, but you have to do it right if you want it to last. That means completely removing the old caulking. And sanding the sides of the groove. And vacuuming all the dust off. And wiping the groove with acetone.

When I did re-caulking on my old HR, it was easy to remove most of the old caulking just by hand, so I haven't experienced using the Fein-type tool. However, I'd be cautious of damaging the sides of the groove - any imperfection will stand out like a sore thumb when you've finished the job.

You say you're planning to use "DS Deck Sealant", which I guess is TDS Deck Sealant. I'd suggest you also consider Sikaflex 290DC, used with Sika Primer-290DC. This will be a bit more work, but it should guarantee excellent adhesion to the sides of the groove. It is also rather more tolerant of humidity - TDS Deck Sealant requires the teak to have less than 12% moisture content, which may be difficult to achieve unless you're doing the job inside a heated workshop.

As duncan99210 also suggested, using masking tape helps to minimise the mess! I found it was useful to have an open-topped cardboard box handy to drop pieces of tape into when I removed them. If you're working outdoors, put a weight in the box to stop it blowing away. Work in sections, only doing as much as you can easily complete in a 2 or 3 hour session. Try to mark the borders of the section in some way, perhaps with different-coloured masking tape, so that you can avoid accidentally stepping on wet seams. Have lots of latex gloves available, plus a kitchen roll and some meths to remove the uncured caulking from your skin and shoes (yes, you will step on it sometime!).

I found a very sharp chisel was the best way of initially removing excess caulking, followed by very light sanding. I used a lightweight Bosch DIY belt sander, very gently, so as not to remove too much precious wood. Afterwards, treat the deck every few months with Boracol and avoid any abrasive cleaning.

Re-caulking is a filthy job, and it scarred me sufficiently that I vowed never to have teak decks again, so I specified fake teak on my new boat! But equally it's a very satisfying job, and looks lovely when you've finished it. Have fun!
 
I think the real key with using a multitool is not to use it at full speed. It is not controllable enough and you will end up taking lumps out of the teak (as I found out to my cost....). I use mine at about half speed and it is very controllable, lifts out the caulk in a long ribbon and is easy to control both in terms of depth and line. Oh, and make sure you keep the blade sharp by honing it against a stone or emery cloth every now and then.
 
Thanks for the advice. I did a small area last year using many of the methods you suggest (I had probably already read your advice on an earlier thread). I was happy with the results using TDS Sealant. This was coincidentally recommended by one boatbuilder and shunned by another?! My local chandler gave a vote to the TDS filler so I was happy to try it. I have to say I am very happy with the result. Only drawback is as you suggest the moisture content needs to be checked but I plan to do the work at the end of the summer. Thanks for the advice and rest assured it's all being noted and I will seek some additional views on TDS VS Sikaflex.
 
Good post by pvb.....thanks for that you've brought back all the mental scars:)

It's what I did/used.I had a mate help when recaulking,made it so much easier.
Only difference was no masking tape on main areas,we found it less messy.Gunned it in,smoothed it down very gently with a flat headed screwdriver to get rid of any air pockets.Only used masking tape around toe rails etc.Worked away from it,then left it for a week to fully cure.Gunned it in higher than the teak,remember reading somewhere on one of many articles I read that it can sag when curing?and I wanted it to be flush.
Removed the excess with a very sharp window blade then sanded it all back.Cured Sika comes off fibreglass ok,rub with your fingers or acetone.
6/7 years on still looks good,I look at it a lot to remind me never to buy another boat with a knackered teak deck!!
 
Last edited:
Flynnbarr said:
Good post by pvb.....thanks for that you've brought back all the mental scars:)
Click to expand...

I don't think I'll ever forget it! I also took out a lot of screws, deepened the holes with a Forsten bit, fitted new low-profile screws, then new teak plugs, then chiselled them flush. Hundreds of the buggers!
 
pvb said:
I don't think I'll ever forget it! I also took out a lot of screws, deepened the holes with a Forsten bit, fitted new low-profile screws, then new teak plugs, then chiselled them flush. Hundreds of the buggers!
Click to expand...

Ditto....I didn't count,would have been to painful....I just left the house each time mumbling I hate that damn boat why did I buy it:)
 
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