8.1 External solid plastering

Transcription

1 8.1 Externl solid plstering Aims nd ojectives At the end of these ctivity sheets, lerners should e le to: understnd the preprtion of ckgrounds identify the mterils used for externl plstering identify the dditives used in externl plstering understnd the different plstering cots nd their ppliction identify the purpose nd position of eds in externl plstering understnd the helth nd sfety issues involved in externl plstering. Tutor guidnce notes These questions nd ctivities re not intended s forml ssessment. However, the nswers should e discussed with the lerners s group to ensure tht they hve full comprehension of the suject. Individul techers will use these questions nd ctivities in different wys. They could e used t the end of session to recp, used individully during the session s tothe-point lerning tool, or used s homework. Whichever teching method is chosen, mke sure tht you set nd gree upon completion dte for ech ctivity. The nswers given re not exhustive nd re to e used s guide only. Alterntive, pproprite nswers my e considered. Cndidte nme: Dte: Plstering NVQ nd Technicl Certificte Level 2 Tutor Resource Disk 1 of 1

2 8.1 Externl solid plstering Aims nd ojectives At the end of these ctivity sheets, you should: Chpter 8: Externl solid plstering understnd the preprtion of ckgrounds identify the mterils used for externl plstering identify the dditives used in externl plstering understnd the different plstering cots nd their ppliction identify the purpose nd position of eds in externl plstering understnd the helth nd sfety issues involved in externl plstering. 1 Wht prolems will poor qulity snd give to n externl render? 2 How should snd e stored on site? 3 Wht re the initil nd finl setting times for cement? 4 Nme two specil types of cement. Plstering NVQ nd Technicl Certificte Level 2 Tutor Resource Disk 2 of 2

3 5 Nme two types of dditive tht cn e dded to n externl render. 6 Wht preprtion should e mde to old rickwork efore pplying n externl render? 7 Wht type of onding dhesive should e pplied externlly? 8 Wht type of externl render should e pplied to insultion ords externlly? 9 Why is sptterdsh cot pplied externlly? 10 Wht mix rtio is required for scrtch cot for externl render? Plstering NVQ nd Technicl Certificte Level 2 Tutor Resource Disk 3 of 3

4 c d 3 : 1 plus wterproofer 4 : 1 plus wterproofer 5 : 1 plus wterproofer 6 : 1 plus wterproofer 11 Wht mix rtio is required for the top cot for externl render? 3 to 4 : 1 : 1 5 or 6 : 2 : 1 c 3 or 4 : 1 : 2 d 5 to 6 : 1 : 1 12 In which cot of render should the wterproofer e put? 13 Wht is the purpose of scrtch cot in externl rendering? 14 Wht is the required thickness of scrtch cot? 15 Wht is the purpose of ellcst? 16 Nme two plces where ellcst ed would e positioned. Plstering NVQ nd Technicl Certificte Level 2 Tutor Resource Disk 4 of 4

5 17 Wht is the minimum time tht scrtch cot should e left efore pplying the top cot? 18 Cn strong cot e lid on top of weker cot? Why/why not? 19 How is the top cot finished off? 20 Nme two mterils tht externl eds cn e mde from. 21 Where is plinth usully pplied? 22 How is cement-sed externl render cured? Plstering NVQ nd Technicl Certificte Level 2 Tutor Resource Disk 5 of 5

6 23 Why do cement-sed externl renders need to e cured? 24 On which cot of render should eds e fixed? 25 Wht common fult is sometimes found on the finish of n externl render? Plstering NVQ nd Technicl Certificte Level 2 Tutor Resource Disk 6 of 6

7 8.1 Externl solid plstering Answers Chpter 8: Externl solid plstering 1 Wht prolems will poor qulity snd give to n externl render? Poor qulity snd will cuse externl renders to crck nd ecome loose nd hollow. The externl render my even crumle when ttcked y wether, especilly in winter. 2 How should snd e stored on site? Snd should e stored in clen y, nd covered with trpulin. 3 Wht re the initil nd finl setting times for cement? 45 mins for the first initil set nd 10 hours to the finl set 4 Nme two specil types of cement. sulphte-resisting Portlnd cement (SRPC), rpid-hrdening Portlnd cement (RHPC) 5 Nme two types of dditive tht cn e dded to n externl render. wterproofer, plsticiser, retrder, ccelertor 6 Wht preprtion should e mde to old rickwork efore pplying n externl render? Hck off old work, rke out joints, rush nd dmpen, nd pply slurry dhesive. 7 Wht type of onding dhesive should e pplied externlly? n SBR 8 Wht type of externl render should e pplied to insultion ords externlly? Use specilist lightweight render ecuse snd nd cement-sed mterils would e too hevy. 9 Why is sptterdsh cot pplied externlly? It is used to produce good qulity key for the externl render to ond onto. Plstering NVQ nd Technicl Certificte Level 2 Tutor Resource Disk 7 of 7

8 10 Wht mix rtio is required for scrtch cot for externl render? 3 : 1 plus wterproofer 4 : 1 plus wterproofer c 5 : 1 plus wterproofer d 6 : 1 plus wterproofer 11 Wht mix rtio is required for the topcot for externl render? 3 to 4 : 1 : 1 5 or 6 : 2 : 1 c 3 or 4 : 1 : 2 d 5 to 6 : 1 : 1 12 In which cot of render should the wterproofer e put? Put it in the scrtch or render cot. 13 Wht is the purpose of scrtch cot in externl rendering? A scrtch cot is pplied to strighten out n uneven ckground. 14 Wht is the required thickness of scrtch cot? The thickness of scrtch cot is etween 9 nd 12 mm. 15 Wht is the purpose of ellcst? The min purpose of ellcst ed is to keep wter wy from the uilding. It is sometimes used s decortive feture. 16 Nme two plces where ellcst ed would e positioned. It is plced over door or window nd just ove the dmp proof course (DPC). 17 Wht is the minimum time tht scrtch cot should e left efore pplying the top cot? Leve it minimum of 24 hours, ut it is est to leve it s long s possile. 18 Cn strong cot e lid on top of weker cot? Why/why not? No, ecuse strong cot will lwys ring off weker cot. 19 How is the top cot finished off? Finish it y the use of flot nd lso sponge flot. 20 Nme two mterils tht externl eds cn e mde from. stinless steel nd plstic Plstering NVQ nd Technicl Certificte Level 2 Tutor Resource Disk 8 of 8

9 21 Why is plinth usully pplied? A plinth is pplied elow the dmp proof course to ground level. 22 How is cement-sed externl render cured? Drping wet cnvs or plstic sheeting down the render finish cn cure externl cement work. 23 Why do cement-sed externl renders need to e cured? Cement needs wter to extend its chemicl setting time. Externl render will e exposed to sunlight nd het, which will dry out the wter nd prevent the cement reching its full strength. 24 On which cot of render should eds e fixed? Beds should e fixed on the scrtch/render cot. 25 Wht common fult is sometimes found on the finish of n externl render? A common fult is crzing, cused y either suction or over-floting the surfce, ecuse this will ring wter nd cement to the surfce. Plstering NVQ nd Technicl Certificte Level 2 Tutor Resource Disk 9 of 9