How to build an extension: part 3 concrete floor slab

[@tyronebishop1719]

This is AMAZING! Thanks guys, I'm building a garden room 30 x 30m so I'm going to follow this model

[@joneschris1171]

Love this series of videos guys. Such brilliant explanation. Gives us novices and diy'ers a good understanding. Thank u so much, don't know where will be without u guys posting these. Thank u once again and keep up the good work.

[@foundationgood123]

Jones Chris Hi, thank you for the heads up. So glad the vids have been helpful😀

[@adamroden7206]

Cracking down to earth trades people doing a great job. Really helpful videos simply explained, love it. Keep up the good work.

[@AddictedtoProjects]

Hi Chris, lovely professional job. And thanks for sharing all the details with us! I wish more builders in the UK would follow your example and be a bit more professional and proud of their work. :)

[@foundationgood123]

Addicted to Projects Thank you😊

[@davidrobinson9275]

Are all your family making comments for you .

[@makanjuolaasimiyuadesoji7402]

Good job thanks for this videos I was expecting to see plumbing installation before the oversight concrete.

[@suetheron4495]

great work, I wish you could do my house! I especially like how you're smoothed it ready for the next trade, very thoughtful

[@britishbluetess]

I’m a tradesman myself chris and you do a bang on job some of the people that comment on here make me laugh, probably wouldn’t know one end of a screwdriver from the other 😂👍🏻

[@stanleyjones1908]

screwdriver,... a special tool for opening tins of paint and the Really long one is for scratching the middle of your back with !!

[@Guide504]

So rare to see pride in work especially nowadays.... Great work guys.

[@lukeetheridgepd]

Superb lads! Literally came to see how you handled the DPM in the corners. Got my answer - top work

[@icarossavvides2641]

Shouldn't the UFH be on the insulation and below the screed? Just asking? Also, where IS the UFH?

[@dnamartey]

Thanks for the video. I'm an architectural student and videos like these are very helpful. 👍

[@Abidsalehuk]

Hi Chris , i want tto say Thank you so much for a brilliant info sharing with us and hope to see upload more useful videos . well done and keep it up.

[@foundationgood123]

Thank you 😊

[@Carl-yu6uw]

Looks a tidy job. Be good to see a following video have bit on the underfloor heating system etc going in up to ffl, if possible?

[@colingreen4625]

Proper job done there...nice one Chris.

[@ZyleenxClubAsiaRadio]

Another very informative video! Thanks

[@detuneCH]

Good video. Can I ask, why did you have two seperate slabs for the two rooms instead of one large slab?

[@CarFinanceSimplified]

Really found this useful. What are your thoughts on block and beam for the floor instead? Great series!

[@johnm8269]

Learn a lot from these vids love groundsworks

[@hotpoker4212]

Great videos,Chris top job,🇮🇪🇮🇪

[@foundationgood123]

Thanks 👍

[@drgrowuk8830]

Great video man so helpful and easy to understand Great workmanship 👏👏👍

[@alucardcount9478]

cant thank u enuf for your vids thank u chris

[@insight7483]

Definitely worth doijg a voice over

[@danwoodgate_bxng]

Above and beyond whats needed, hats off to you guys. Love this game we're in 👍

[@construction-productscemen4935]

Thanks for sharing all the details with us.

[@foundationgood123]

Thank you -:)

[@Familygarden88]

Thanks for sharing, excellent work!

[@foundationgood123]

Thank you! Cheers!

[@GazMan82]

Nice job, screed thickness?

[@richnottmforestmarley4347]

Ok Chris good work good videos

[@Triggaaar]

Good video, finish looks excellent. Looks like you skimped a fair bit on the 150mm of hardcore, there was never 4" of Type 1 before the blinding sand.

[@foundationgood123]

No its layered and whackered down! Never put the full 100mm and whacker it as it doesn't compact it down that depth. I cut the time laps or jumped it to cut time down..

[@johnbowkett5920]

150 mm of stone ? .... I'm always more concerned about the Jablite or Kingspan under the floor . Think about it !

[@andrewwatt9770]

Loved you video. So neat on site. Well done good explanation. Must give you a good feeling at the end of the job. Satisfied

[@davidwood8837]

Could you use two sheets of 50mm insulation on top of each other? Just material shortages cant get hold of 100mm. Thanks and great channel

[@foundationgood123]

Possibly!

[@TheAudiostud]

Another cracking production Chris!

[@neilnash2383]

Beautiful work boys

[@Bananas331]

Looks brilliant.

[@richnottmforestmarley4347]

Nice to see it doing the right way 👏

[@robgood719]

Top job lads nice to see

[@Airportfleetcouk]

Top Class Work and very pleased with it. Many thanks for sharing.

[@foundationgood123]

Thank you-:)

[@shawnlarry8943]

Great work, Christ

[@TeeTee-zm2re]

Is the two inch upside insulation sat on the four inch or is is wedged between?

[@andylewisfoodphotography4223]

Hey guys - great video. I see a few people have asked the same questions but I think I’ve made sense of them. Is the reason you didn’t do it in one slab was because you had a wall between the two rooms and you could put the wall on top of the slab because there was no reo used?

[@davidrobinson9275]

Good job lads nice to see someone who knows the game also does a very good job without all the phoney jobbers patter off how technically the job gets ,when you know what your doing it should be like water of a ducks back without all the bull,,,,t just like Chris has done .

[@WILDINGGARDENINGSERVICES]

Hello mate. I’m doing an extension myself. I put the visqueen plastic down and hard-core on top of that. Will this affect the building in anyway I am yet to finish off the flooring, but I’m wondering if I done this stage of the build Thanks

[@foundationgood123]

First it’s MOT type 1 or as you called it, Hard-core, then secondly it’s a 50mm sand blinding (stops sharp stones puncturing the visqueen/plastic then a layer of visqueen then insulation then visqeen again

[@troytheboy1990]

@@foundationgood123 Thank you for your reply I know about the visqueen on top of the sand then on top of the insulation but because the ground was soaking wet mud would it be detrimental to the overall structure there being a extra membrane and the mot type 1 or will it be fine?

[@m.a.9471]

Good job and educating video mate , thank you 🙏

[@emrajsingh3414]

Solid job... clear instructions... Are you using building sand or sharp sand for the 2 inch layer on top of hardcore ??

[@foundationgood123]

Emraj Singh Hi, I think it was Sharp sand but it doesn’t really matter which

[@shawnlion4778]

Good work brothers

[@otecfabricationstynagh6365]

Very good job lads. But why the lawnmower?

[@MrMiss]

Hi man. Awesome video. What was the layer that went down after you wackered the hard core? Was it sand? Cheers

[@foundationgood123]

Hi matey, yes it was 50mm of sharp sand!

[@ikky221]

Was the visqueen gas barrier just one single sheet. We had to have one gas barrier sheet and use double sided tape to atach a seperate gas resistant dpc.

[@womblestacker7993]

Can't wait to start mine next year

[@watkins525]

What's the purpose of having the cavity continue through on the side where the smaller part of the building joins on? Can just be single skin can it not?

[@hants1]

Would you use this for a conservatory base aswell?

[@foundationgood123]

hants1 Yes thats the same way

[@RUH24A]

Hello. I noticed the house we purchased the extention attached to the house - the flooring does not have insulation. There is a membrane and 4" concrete on the floor. However is there an option i could insalate the floor before we decide to put either laminate or carpet down? Thanks in advance

[@JackKing12.]

1:48...that is one beer belly 🤣...besides the bellies...good job...but...no expanding strip foam to the perimeter? Or A mesh reinforcement?

[@asef698]

Mesh reinforcement for that size 😂

[@andrekidd6871]

Was there a need for air bricks in extension ?

[@kenboon1478]

Did you put a time capsule in the concrete ?

[@jaggiguru3127]

very good idea water problem

[@Hena-gc3cx]

Looks like a good job. I am getting an extension and the builders have only prepared a foundation around 300m deep, comprising of 100ml hardcore, 100ml Insulation and 100ml concrete (plus damp 2 X covers). Do you think this is sufficient? I am worried it is not.

[@foundationgood123]

Hanna Sounds up to regs, you could always add reinforcement mesh which will really strengthen it!

[@grahamcole4240]

Great job.

[@duncanboolay9424]

How long before you can walk on it ?

[@foundationgood123]

Depending on the weather, we pored it and because it was hot the concrete started going off and within 2/3 hours it had gone off enough and we were walking on it.in 2 hours, just enough time to trowel it up. Ready mix concrete a C25/30starts going off in 30 minuets so that will help you to determine it and of course the weather conditions to factor in!

[@yasminghani2073]

Great job

[@criartoros]

Brilliant job. Is it possible to do the concrete base in sections?

[@foundationgood123]

criartoros Its better done all together and use ready mix concrete as its more uniform! Hope that has helped

[@lameduck3630]

What do you think of Peter Ward's philosophy that cement is the devil's work and lime is the only solution?

[@broughtonpb]

Looks very thin that slab!no re-enforcing steel mesh on 50mm spacers?🤔

[@karljones1905]

Cann I use insulation boards for the cavity on my 3mtr extension the board's I'm talking about they use them on new builds so I would b surprise if I couldn't thanx m8

[@foundationgood123]

Yes, they fix them with fixer screws with large plastic washers

[@tramhicks1215]

If I go back to Vietnam l can build it like this.

[@Ruccy007]

You did not put any armature in the plate???

[@m.a.9471]

Exllent job mate

[@tonboy8518]

Why no mention of underground drainage ?

[@brucedickinson12]

how do you extend central heating pipes if you have done a concrete floor ???

[@johnlink7501]

If this method has been followed but a couple of years later the floor sinks by about 5cm in one corner what could be the possible causes and how can it be put right

[@MrDweb]

Only 1 barrow?

[@Alb4418]

Do you think a house built in 1985 have installation boards under the screed?

[@foundationgood123]

possibly not..came in in the early 1990s

[@zahirnaseem542]

Nice work

[@joinmichael6345]

Thanks for sharing... very useful to know

[@TiberiusWorld]

how much was the labour bill for this??

[@riaahmed2949]

Really helpful thank you for this video.

[@chalruk2050]

Is it okay to put concret slap on top of 4" insulation. Won't it sink down over time.? and what is tha insulation called again..?

[@Palo-jm7xc]

it's fine to do that with the concrete as long as you have to insulation up stand around the edges, this allows the concrete to expand and contract without moving the walls, as well as reducing cold bridging. its also a spread load so is unlikely to compress. PIR is the insulation. Or Celotex, Kingspan or Quinntherm are some of the brands.

[@TurinTuramber]

The insultation is very strong at taking spread loading forces. The slab goes on top of insulation so the heating will heat up the concrete slab, this acts as a thermal mass store which will give a much more stable heat source.

[@gb7729]

can i ask what type of sand to use for the blinding

[@foundationgood123]

There are several sands, sharp sand, plastering sands and building sand....Ask for building sand and tge merchants will know what you want it for

[@MatthewFrost]

Ive dug my floors out to soil and i am having UFH. Do i need to do all the insulation and slab depth as above in the video, then again another 100mm kingspan for the UF pipework and then another 50-65mm screed on top of that then tile?

[@stiggy1250]

Hi I’ve done the same just wondering what you did ? Double insulation or ?

[@mrdougals1]

Top job

[@BibiRozitaProduction]

Is it work if I use that.blue thing to concerete my top slab which is I dont have roof.. Is it waterrproof?

[@foundationgood123]

The blue stuff is visqueen commonly know as plastic it’s a 500 Gauge plastic and is waterproof! Hope this helps!

[@BibiRozitaProduction]

@@foundationgood123 thanks

[@chick262]

Why doesn't the plastic come down over the outside skin

[@qfactor77]

I wish it showed how the first polythene sits against the wall of the of the house.

[@nbnbio1223]

بس شغلك حلو ومرتب👍👍👍👍👍👍👍👍

[@ChristopherClaudioSkierka]

Hi there I knwo its been a while since you did this video but I was looking in drilling into my concrete floor to attach a plinth (ground floor) but I do not want to screw into the DPM , I will probably go around 30mm through the concrete. Do you think I may hit it? please note these are a new build 2021. thanks i8n advance

[@foundationgood123]

High the minimum depth of the concrete substrate is 100mm(4”) then there’s usually a screed of min 70mm! That should give you an idea of how much allowance you have got. Hope this helps

[@ChristopherClaudioSkierka]

@@foundationgood123 excellent thanks for the reply. I am really surprised I have that much to play with. I was expecting around 1 inch ! So basically I am going to go into the screed with 30mm depth of drilling ,, relieved actually :)

[@user-ww7wz2gs4s]

good job !!

[@BillySnowball]

Neat job

[@alisharif1997]

Good man keep do what you doing 🏘️🏗️🏘️🏘️🏘️🏘️🏘️🏘️🏘️🏘️

[@Gd9967-s2b]

Hi. Quick question. What is the sense of insulating the floor if the horizontal insulation of the walls has not been applied, which will cause the capillary rise of water from the ground. This will cause the walls to become damp.

[@stevothabasta5278]

Hi quick question , since when do you insulate cavity walls below dpc ?

[@rossprivate5456]

because of the insulation is no re-bar used? .im an aussie and have never seen insulation used under a slab ,is this for snow/ice freezing? we dont have a freezing soil problem here, good job !

[@israeladesanya4596]

Insulation especially with the underfloor heating

[@chelseaant1]

What happens to the damp that connects to the existing rear of house please? Could damp still rise behind it? Thanks

[@andylewisfoodphotography4223]

chelseaant1 - I’m keen to know the answer to this also. I was wondering if a liquid rubber could be used to stick the damp layer to the brickwork?

[@richnottmforestmarley4347]

Under floor heating pipes normally go on top off insulation then concrete

[@foundationgood123]

Rich Nottmforest Marley Its having a laytex pour over next

[@stevendunn5430]

Rich Nottmforest Marley. I thought this myself as i am on a sight with this procedure and is done as you said with a DPM protection cavity tray around the perimeter of the building above FFL for safety purposes? Correct me of im wrong?

[@stevendunn5430]

Not saying you dont know what you are doing but a different way is what i have witnessed?

[@foundationgood123]

I'll try and film it when it goes in and put it up and we can both see- how it done this way:)

[@BK-it6te]

Chris Longhurst which aria you are working Would you be interested Building a massive extension?

[@jeroenbezuijen3767]

And they missed the concretesteel in groundfloor and perhaps in foundation.

[@criartoros]

These guys are experts. Your a cowboy, head for the hills

[@scalereality4840]

UK House-building foundations don't use steel unless they are pile foundations.

[@scalereality4840]

@@nocturn791 They didn't 'miss' it, UK foundations are deep concrete to support the walls, different to the USA were a very shallow concrete pad is poured that needs rebar/steel to hold it together as it sits on soil.

[@ddk4664]

Nice !

[@shazgee1996]

On the start of video it says 500mm gauge membrane visquine then you say its 1000mm which one is it

[@foundationgood123]

1000

[@RawiriG69]

You Americans do it so hard omg

[@leemarley816]

You do top class work to a high standard chriss.but please stop using a level to tamp and screed concrete with. makes you look like some sort of a bengal lancer or a john wayne.get yourself a long straight piece of wood and put the level on top.

[@foundationgood123]

Lee Marley Hahaha true.. I used that method in part one(have a look). But in my defence I did say we had run out of straight edges on the site lol 😂

[@foundationgood123]

bernard bernard True, but this isn’t “screed” it’s “over-site concrete” Over-site is usually a rough tamped slab and a semi dry screed on top which needs more accuracy as its semi dry!

[@cheshstyles]

Never heard bengal lancer lol. Looks like he did a fine job with the level

[@christianiroh4493]

I can't see a subfloor ventilation pipe!!!

[@gaza8432]

Rich coming from lee Marley ? I hope it's not brickwork !!!

[@Hofsterman]

3:35 I think the man did a hole with the wheelbarrow through DPM 😏

[@kwempe]

It actually doesn't matter if it did make a hole that is the 2nd layer of DPM above the insulation. It is also known as a slip layer. The DPM layed direct to the sand is the one that keeps the damp at bay

[@Hofsterman]

@@kwempe I know. Just being silly. Sorry

[@garyharris184]

I was always told min screed above the depth off pipe is 65mm even with flow screed and min insulation is 140 mm under the concrete ??

[@skilledbuilduk9694]

50mm flow screed is standard where where we live and also as little as 75mm foil board under the slab on extensions.

[@avnishparkash7792]

No need for a reinforcing mesh?