advice on costing for fixing kerdi coll and keba

[jonnyc]

I have posted this in trusted advisors as i think there will be another member who is not a trusted advisor who will costing for this job as well.
quoting to supply and fix limestone in a church which is about 100 years old.
there is currently wood block flooring ( which has dry rot )set in bitumen over a 6 inch concrete base.
the suggestion is that builder will remove the wood block/bitumen and make good sub floor.
i would then come in and latex over whole area and put down ditra taping all joints with keba tape and lapping tape up to floor level . I actually think this is a bad idea if there is a damp problem as the damp will be forced sideways to walls and columns if keba tape and kerdi coll adhesive used correctly.
there is about 310 sq mts ditra to fix which is quite expensive in otself but add the keba tape and kerdi coll adhesive and labour and this gets really expensive .
there is 450 lin mts of tape to be used and i have worked out it will need 15 x 30 mts keba tape and 38 tubs x 4.25 kg kerdi coll.
what would you charge to fix 450 lin mts keba tape

 

[Spud]

the bitumen will be acting like a dpm anyway jonny so if there is not a damp issue now there wont be one if you fit ditra ,why are you thinking of kerdi coll to stick the ditra down with ? i would be inclined just to use spf and then just use the kerdi coll on the joints to stick the keba down with, also have you costed buying a 30m roll of kerdi and cutting this into 100mm strips yourself, I have not done this but it may work out cheaper than buying rolls of keba which is just kerdi cut into strips

 

[jonnyc]

i agree that the bitumen will have been acting like a dpm provided it is still in place and intact when block flooring removed.
but architect has specified that this bitumen be removed before latexing over and then ditra made .
would you latex over bitumen if still intact and then ditra over.
i was not thinking of using kerdi coll to stick down ditra . that would be stuck with spf .
just to stick the 450 lin mts keba down would need 160 kg of kerdi coll.
if there is a damp problem i am thinking more along the lines of fixing stone in lime/sand and then using dry treat to let the stone breath but i still want something as a separating membrane in a big area like this that is breathable.
i have done a couple of private abbeys in the past which had serious damp problems as abbey near to river but this was private and they took chance of not having ditra. it has been fine .

 

[jonnyc]

youre right gary
just looked up kerdi matting and it is cheaper by factor 4.40:1
not got my business head on ;
i reckon it will take 4.50 - 5 days just to stick the tape down.
i know how long it takes to lay ditra and cover with adhesive