Hellulagnir fela \u00ed s\u00e9r \u00fatlagningu \u00e1 hellum, steyptum e\u00f0a n\u00e1tt\u00farulegum. Mikilv\u00e6gt er a\u00f0 hellur s\u00e9u valdar me\u00f0 tilliti til \u00feess \u00e1lags sem \u00e1 sv\u00e6\u00f0inu ver\u00f0ur, t.d. hvort um s\u00e9 a\u00f0 r\u00e6\u00f0a umfer\u00f0arg\u00f6tu, innkeyrslu e\u00f0a g\u00f6ngust\u00edg. \u00cd dag er \u00farval steinsteyptra hellna miki\u00f0 og g\u00e6\u00f0i framlei\u00f0slunnar \u00ed flestum tilfellum g\u00f3\u00f0.\u00a0 \u00c1 \u00cdslandi er ekki miki\u00f0 um a\u00f0 n\u00e1tt\u00farugrj\u00f3t s\u00e9 nota\u00f0 \u00ed hellulagnir en \u00fea\u00f0 hefur \u00fe\u00f3 f\u00e6rst \u00ed v\u00f6xt \u00e1 s\u00ed\u00f0ustu \u00e1rum. Sem d\u00e6mi m\u00e1 nefna hraun-, gran\u00edt- og basaltfl\u00edsar, br\u00fasteina- og oddsteinalagnir.<\/p>\n
Mikilv\u00e6gt er a\u00f0 vel s\u00e9 huga\u00f0 a\u00f0 undirb\u00faningi og undirbyggingu. Best er a\u00f0 m\u00e6la upp sv\u00e6\u00f0i\u00f0 , leggja \u00fat sn\u00farur og gera s\u00e9r grein fyrir h\u00e6\u00f0 fyrirhuga\u00f0s yfirbor\u00f0s me\u00f0 tilliti til n\u00e6rliggjandi sv\u00e6\u00f0a og mannvirkja. Tryggja \u00fearf a\u00f0 vatn eigi grei\u00f0a lei\u00f0 um yfirbor\u00f0i\u00f0 og \u00ed r\u00e9ttar \u00e1ttir, t.d. \u00ed ni\u00f0urf\u00f6ll. Algengt vi\u00f0mi\u00f0 er a\u00f0 halli \u00e1 yfirbor\u00f0i s\u00e9 l\u00e1gmark tveir sentimetrar \u00e1 hvern metra. \u00a0\u00cd flestum tilfellum er nau\u00f0synlegt a\u00f0 jar\u00f0vegsskipta undir hellulagnir, til a\u00f0 tryggja bur\u00f0 og hindra frostlyftingar. \u00c1\u00f0ur en \u00fea\u00f0 er gert \u00fearf a\u00f0 kanna hvort lagnir liggi undir graftrarsv\u00e6\u00f0um og taka tillit til \u00feeirra vi\u00f0 \u00fatgr\u00f6ft. \u00deykkt og uppbygging bur\u00f0arlagsins fer eftir \u00fev\u00ed \u00e1lagi sem \u00e1 sv\u00e6\u00f0inu ver\u00f0ur. Algengt er a\u00f0 jar\u00f0vegsskipti s\u00e9u fr\u00e1 50-100 sentimetrar, h\u00e1\u00f0 jar\u00f0vegi og \u00e1lagi. \u00cd bur\u00f0arlag \u00fearf a\u00f0 nota efni sem \u00fejappast vel\u00a0 og ver\u00f0ur ekki fyrir frost\u00e1hrifum, t.d.\u00a0 gr\u00f3fa gr\u00fas. Gr\u00fasina \u00fearf a\u00f0 \u00fejappa me\u00f0 jar\u00f0vegs\u00fej\u00f6ppu, lagskipt \u00ed um \u00fea\u00f0 bil 20 sentimetra l\u00f6gum. \u00deegar gr\u00fas hefur veri\u00f0 sett \u00ed r\u00e9ttar h\u00e6\u00f0ir er svok\u00f6llu\u00f0um hellusandi jafna\u00f0 yfir sv\u00e6\u00f0i\u00f0 og hann \u00fejappa\u00f0ur. Algengt er a\u00f0 hellusandur s\u00e9 haf\u00f0ur \u00ed u.\u00fe.b. fimm sentimetra lag\u00feykkt (\u00feykkari \u00feegar snj\u00f3br\u00e6\u00f0sla er l\u00f6g\u00f0 undir hellur). Til a\u00f0 sl\u00e9tta hellusandinn \u00ed r\u00e9ttar h\u00e6\u00f0ir eru yfirleitt nota\u00f0ir lei\u00f0arar, t.d. j\u00e1rn-vatnsr\u00f6r sem eru stillt af \u00ed grafin ni\u00f0ur \u00ed samr\u00e6mi vi\u00f0 \u00e1\u00f0ur m\u00e6ldar og \u00fatsettar h\u00e6\u00f0ir. Yfir lei\u00f0arana er s\u00ed\u00f0an dregin r\u00e9ttskei\u00f0 sem tryggir a\u00f0 yfirbor\u00f0i\u00f0 ver\u00f0i jafnt og \u00ed samr\u00e6mi vi\u00f0 h\u00e6\u00f0arsetningar. \u00deessi a\u00f0ger\u00f0 er yfirleitt k\u00f6llu\u00f0 \u201estraujun\u201c af fagm\u00f6nnum. S\u00e9 um beina hellul\u00f6gn a\u00f0 r\u00e6\u00f0a er yfirleitt settar upp st\u00fdril\u00ednur til a\u00f0 tryggja a\u00f0 l\u00f6gnin ver\u00f0i bein og hornr\u00e9tt. Hellur m\u00e1 leggja me\u00f0 \u00fdmiskonar mynstri, \u00fe\u00f3 h\u00e1\u00f0 helluger\u00f0. G\u00e6ta \u00fearf \u00feess a\u00f0 bil, einnig kalla\u00f0 f\u00faga, s\u00e9 \u00e1 milli hellna sem eykur styrk og kemur \u00ed veg fyrir a\u00f0 brotni upp \u00far k\u00f6ntum. Fyllt er \u00ed f\u00fagur me\u00f0 svok\u00f6llu\u00f0um f\u00fagusandi. Til a\u00f0 tryggja styrk og endingu hellulagnar \u00fearf yfirleitt a\u00f0 steypa me\u00f0fram k\u00f6ntum og gott er a\u00f0 lj\u00faka verkinu \u00e1 a\u00f0 \u00fejappa yfir sv\u00e6\u00f0i\u00f0 me\u00f0 l\u00e9ttri jar\u00f0vegs\u00fej\u00f6ppu.<\/p>\n